Comprehensive Previous Year Questions (PYQ) List (2017–2025)

Compiled by Devashish & Sriyans

This compilation includes each and every question extracted from the provided sources for the years 2017, 2018, 2019, 2020, 2023, 2024, and 2025, organized chapter-wise.

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Chapter 1: Cell Structure and Division (Mitosis, Meiosis, Cell Cycle)

Year Q No. Question
2017 Q1(d)(iv) Rewrite the terms in correct order in a logical sequence: Uterus, Parturition, Fertilisation, Gestation, Implantation. (Note: This question contains reproduction terms but includes Gestation/Parturition sequence, often taught alongside cell cycle timing basics).
Show Answer
Correct Sequence: Fertilisation → Implantation → Gestation → Parturition
Note: Uterus is the organ where these processes occur, not a step in the sequence.
2017 Q1(f)(ii) Complete the second pair on a similar basis: Cytoplasm : Cytokinesis : : Nucleus : ____________
Show Answer
Answer: Karyokinesis
Explanation: Cytokinesis is division of cytoplasm, so nucleus divides by karyokinesis.
2017 Q1(f)(iii) Complete the second pair on a similar basis: TT : Homozygous : : Tt : ____________
Show Answer
Answer: Heterozygous
Explanation: TT has identical alleles (homozygous), Tt has different alleles (heterozygous).
2017 Q1(b)(v) Synthesis phase in the cell cycle is called so, because of the synthesis of more: A. RNA, B. RNA and proteins, C. DNA, D. Glucose.
Show Answer
Answer: C. DNA
Explanation: Synthesis phase (S-phase) involves DNA replication.
2017 Q2(a)(i) Study the diagram given below which represents a stage during the mitotic cell division and Identify the stage giving suitable reasons.
Show Answer
Answer: Anaphase
Explanation: Chromatids have separated and are moving towards opposite poles.
2017 Q2(a)(ii) Name the parts numbered 1 and 2 (in the mitotic division diagram).
Show Answer
Answer: 1. Chromatids, 2. Spindle fibres
Note: Based on typical diagram representation.
2017 Q2(a)(iii) What is the technical term for the division of nucleus?
Show Answer
Answer: Karyokinesis
2017 Q2(a)(iv) Mention the stage that comes before the stage shown in the diagram. Draw a neat labelled diagram of the stage mentioned.
Show Answer
Answer: Metaphase
Explanation: Before anaphase comes metaphase where chromosomes align at equatorial plate.
2017 Q2(a)(v) Which is the cell division that results in half the number of chromosomes in daughter cells?
Show Answer
Answer: Meiosis
2019 Q6(b)(i) Study the diagram representing a stage during mitotic cell division. Identify the stage by giving a suitable reason.
Show Answer
Answer: Metaphase
Explanation: Chromosomes are aligned at equatorial plate and attached to spindle fibres.
2019 Q6(b)(ii) Is it a plant or an animal cell? Give a reason to support your answer.
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Answer: Animal cell
Explanation: Presence of centrioles at poles (if visible) or absence of cell plate formation.
2019 Q6(b)(iii) Draw a neat, labelled diagram of the stage which follows the one shown in the diagram.
Show Answer
Answer: Anaphase diagram
Explanation: After metaphase comes anaphase where chromatids separate.
2019 Q6(b)(iv) How many chromosomes will each daughter cell have after the completion of the above division?
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Answer: Same number as parent cell (diploid number)
Explanation: Mitosis maintains chromosome number.
2020 Q4(b)(v) Differentiate between Metaphase and Anaphase on the basis of Position of chromosomes.
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Answer:
Metaphase: Chromosomes align at equatorial plate.
Anaphase: Chromatids move towards opposite poles.
2020 Q5(b)(x) Give the biological/technical term for a non-dividing phase of the cell cycle where more DNA is synthesised.
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Answer: Synthesis phase (S-phase)
2023 Q1(xv) During the synthesis phase of the cell cycle, more of: (c) DNA is synthesised.
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Answer: c. DNA is synthesised
Explanation: S-phase involves DNA replication.
2023 Q1(vi) Haploid number of chromosomes are found in: (d) Sperms.
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Answer: d. Sperms
Explanation: Gametes (sperms and ova) are haploid.
2023 Q2(i)(a) Name the organelle that forms the aster during cell division.
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Answer: Centriole
2023 Q3(iii) Differentiate between Karyokinesis and Cytokinesis.
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Answer:
Karyokinesis: Division of nucleus
Cytokinesis: Division of cytoplasm
2024 Q1(i) Duplicated chromosomes are joined at a point termed: (b) Centromere.
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Answer: b. Centromere
2024 Q1(xii) A male gorilla has 48 chromosomes... How many chromosomes will each of the sperms have? (a) 24.
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Answer: a. 24
Explanation: Sperms are haploid, so chromosome number is halved (48/2 = 24).
2024 Q8(v)(a) The diagram given below represents a stage in mitosis. Identify the stage given above.
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Answer: Anaphase
Explanation: Chromatids have separated and are moving to poles.
2024 Q8(v)(c) Mention the number of chromosomes given in the diagram.
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Answer: 4 chromosomes (as 8 chromatids visible in anaphase)
Note: Assuming typical diagram with 4 chromosomes.
2025 Q1(x) A phase of cell division where the spindle fibres disappear is: (a) Telophase.
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Answer: a. Telophase
2025 Q3(v) Draw a neat, labelled diagram of an animal cell showing Metaphase with four chromosomes.
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Answer: Diagram showing:
1. Four chromosomes aligned at equatorial plate
2. Spindle fibres attached to centromeres
3. Centrioles at poles
4. Nuclear membrane absent
5. Astral rays visible

Chapter 2: Genetics and Evolution

Year Q No. Question
2017 Q1(e)(iv) Choose the ODD one out: Phosphate, RNA, Sugar, Nitrogenous base. Name the CATEGORY to which the others belong.
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Answer: RNA is odd one out
Category: Others are components of a nucleotide
2017 Q1(f)(v) Complete the second pair on a similar basis: Adenine : Thymine : : Cytosine : ____________.
Show Answer
Answer: Guanine
2017 Q1(g)(iii) Match DNA and histones with nucleosome.
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Answer: DNA and histones → Nucleosome
2017 Q6(b)(ii) Give appropriate biological / technical terms for The suppressed allele of a gene.
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Answer: Recessive allele
2017 Q6(b)(vi) Give appropriate biological / technical terms for A pair of corresponding chromosomes of the same size and shape, one from each parent.
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Answer: Homologous chromosomes
2017 Q7(a)(i) What is the phenotype and genotype of the F1 generation if a plant bearing pure axial flowers is crossed with a plant bearing pure terminal flowers?
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Answer:
Phenotype: All axial flowers
Genotype: All heterozygous (Aa)
Assumption: Axial (A) dominant over terminal (a)
2017 Q7(a)(ii) Draw a Punnett square board to show the gametes and offsprings when both the parent plants are heterozygous for axial flowers.
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Answer:
Punnett Square:
Gametes: A and a from each parent
Offspring: AA, Aa, Aa, aa
Phenotypic ratio: 3 axial : 1 terminal
2017 Q7(a)(iii) What is the phenotypic ratio and genotypic ratio of the above cross shown in (ii).
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Answer:
Phenotypic ratio: 3 axial : 1 terminal
Genotypic ratio: 1 AA : 2 Aa : 1 aa
2017 Q7(a)(iv) State Mendel's Law of Dominance.
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Answer: In a pair of contrasting characters, one character is dominant over the other which remains recessive. In F1 generation, only the dominant character is expressed.
2017 Q7(a)(v) Name two genetic disorders commonly seen in human males.
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Answer: Colour blindness, Haemophilia
2018 Q1(e)(v) Correct the following statement: Nitrogen bonds are present between the complementary nitrogenous bases of DNA.
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Answer: Hydrogen bonds are present between the complementary nitrogenous bases of DNA.
2018 Q3(b)(v) Draw a neat labelled diagram of a chloroplast. (Note: While Chloroplast structure is C3, its DNA/replication links to C2).
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Answer: Diagram showing:
1. Double membrane
2. Grana (stacks of thylakoids)
3. Stroma
4. Lamellae
5. DNA and ribosomes in stroma
2018 Q3(b)(ii) Represent the process of photosynthesis in the form of a balanced equation.
Show Answer
Answer: 6CO₂ + 12H₂O → C₆H₁₂O₆ + 6O₂ + 6H₂O
2018 Q4(b)(iv) The condition in which a pair of chromosomes carry similar alleles of a particular character (Technical term).
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Answer: Homozygous condition
2018 Q4(b)(v) The complex consisting of a DNA strand and a core of histones (Technical term).
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Answer: Nucleosome
2018 Q7(b)(i) Give the phenotype and genotype of the F1 generation (GGII x ggii). Which type of pollination has occurred to produce F1 generation?
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Answer:
Phenotype: Green inflated pods
Genotype: GgIi (heterozygous for both traits)
Pollination: Cross-pollination
2018 Q7(b)(ii) Write the phenotypic ratio of the F2 generation.
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Answer: 9:3:3:1
9 Green inflated : 3 Green constricted : 3 Yellow inflated : 1 Yellow constricted
2018 Q7(b)(iii) Write the possible combinations of the gametes that can be obtained if two F1 hybrid plants are crossed.
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Answer: GI, Gi, gI, gi (from each parent)
2018 Q7(b)(iv) State Mendel's law of 'Segregation of Gametes'.
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Answer: During gamete formation, the alleles of a pair segregate or separate from each other and pass into different gametes. Each gamete carries only one allele of each character.
2018 Q7(b)(v) What is the scientific name of the plant which Mendel used for his experiments on inheritance?
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Answer: Pisum sativum (Garden pea)
2019 Q1(a)(iv) Name a pair of corresponding chromosomes of the same shape and size and derived one from each parent.
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Answer: Homologous chromosomes
2019 Q1(b)(i) Correct and rewrite the statement: The theory of Inheritance of Acquired Characters was proposed by Watson and Crick.
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Answer: The theory of Inheritance of Acquired Characters was proposed by Jean Baptiste Lamarck.
2019 Q1(f)(iv) Choose the ODD one out: Chicken pox, Colour blindness, Haemophilia, Albinism. Name the category to which the others belong.
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Answer: Chicken pox is odd one out
Category: Others are genetic disorders
2019 Q1(g)(iv) Expand the abbreviation DNA.
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Answer: Deoxyribonucleic Acid
2019 Q5(b)(i) Identify Australopithecus and Neanderthal man from the pictures.
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Answer:
Australopithecus: More ape-like, smaller brain, prognathous face
Neanderthal man: More human-like, larger brain, prominent brow ridges
2019 Q5(b)(iii) Who proposed the theory of 'Natural Selection'?
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Answer: Charles Darwin
2019 Q5(b)(iv) Name the organism used as an example to explain 'Industrial Melanism'.
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Answer: Peppered moth (Biston betularia)
2019 Q6(a)(i) What is the phenotype and genotype of the F1 generation if a homozygous tall plant is crossed with a homozygous dwarf plant?
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Answer:
Phenotype: All tall plants
Genotype: All heterozygous (Tt)
2019 Q6(a)(ii) Draw a Punnett square board to show the gametes and offspring when both the parents are heterozygous for tallness.
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Answer:
Punnett Square: Tt × Tt
Gametes: T and t from each parent
Offspring: TT, Tt, Tt, tt
2019 Q6(a)(iii) What is the phenotypic ratio and genotypic ratio of the above cross in (ii)?
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Answer:
Phenotypic ratio: 3 tall : 1 dwarf
Genotypic ratio: 1 TT : 2 Tt : 1 tt
2019 Q6(a)(iv) State Mendel's Law of Dominance.
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Answer: In a pair of contrasting characters, one character is dominant over the other which remains recessive. In F1 generation, only the dominant character is expressed.
2019 Q6(a)(v) What is a Dihybrid Cross?
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Answer: A cross between two individuals considering two contrasting traits at a time.
2019 Q6(b)(v) Name the four nitrogenous bases.
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Answer: Adenine, Thymine, Guanine, Cytosine
2020 Q1(b)(i) Explain the term Allele.
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Answer: Alternative forms of a gene occupying the same locus on homologous chromosomes and controlling the same character.
2020 Q1(b)(iv) Explain the term Phenotype.
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Answer: The observable physical or biochemical characteristics of an organism determined by both genetic makeup and environmental influences.
2020 Q1(d)(iv) Rewrite the terms in correct order in a logical sequence: Australopithecus, Cro-Magnon Man, Homo erectus, Neanderthal Man, Homo sapiens.
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Answer: Australopithecus → Homo erectus → Neanderthal Man → Cro-Magnon Man → Homo sapiens
2020 Q3(b)(v) Biological reason: Homo sapiens sapiens is the most highly evolved form of man.
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Answer: Because Homo sapiens sapiens has the largest and most complex brain, highest intelligence, advanced tool-making skills, language development, and cultural development.
2020 Q5(b)(ix) Give the technical term for A sudden inheritable change in one or more genes.
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Answer: Mutation
2020 Q7(a)(i) What is the phenotype and genotype of F1 individuals (TTRR x ttrr)?
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Answer:
Phenotype: All tall with round seeds
Genotype: All TtRr (heterozygous for both traits)
2020 Q7(a)(ii) Write the possible combination of gametes that are obtained when two F1 hybrid plants are crossed.
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Answer: TR, Tr, tR, tr (from each parent)
2020 Q7(a)(iii) Mention the phenotypic ratio of the F2 generation.
Show Answer
Answer: 9:3:3:1
9 Tall round : 3 Tall wrinkled : 3 Dwarf round : 1 Dwarf wrinkled
2020 Q7(a)(iv) State Mendel's Law of Independent Assortment.
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Answer: When two pairs of traits are combined in a hybrid, segregation of one pair of characters is independent of the other pair of characters.
2020 Q7(a)(v) Name two X-linked disorders found in humans.
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Answer: Colour blindness, Haemophilia
2023 Q4(i) Expand the abbreviation – DNA.
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Answer: Deoxyribonucleic Acid
2023 Q4(iii) Mention the two pairs of nitrogenous bases which pair with each other with hydrogen bonds.
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Answer: Adenine-Thymine (A-T), Guanine-Cytosine (G-C)
2023 Q4(iv) State Mendel's 'Law of Segregation'.
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Answer: During gamete formation, the alleles of a pair segregate or separate from each other and pass into different gametes. Each gamete carries only one allele of each character.
2023 Q8(i) Define the term Mutation.
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Answer: A sudden, inheritable change in the genetic material (DNA) of an organism.
2023 Q8(ii) Draw a Punnett square to find out the Phenotypic and Genotypic ratios of the progeny belonging to the F2 generation (Pure breeding red (RR) x pure breeding white (rr)).
Show Answer
Answer:
F1: All Rr (red)
F2: RR, Rr, Rr, rr
Phenotypic ratio: 3 red : 1 white
Genotypic ratio: 1 RR : 2 Rr : 1 rr
2024 Q1(x) Who gave the correct examples of genetic disorders? P, Q, R, S options. (R. Haemophilia and Colour blindness, S. Haemophilia and Albinism)
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Answer: R. Haemophilia and Colour blindness
2024 Q1(xv) Industrial Melanism was observed in: (b) Peppered Moth.
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Answer: b. Peppered Moth
2024 Q2(ii)(a) Arrange and rewrite the terms in each group in the correct order: Australopithecus, Cro-Magnon, Homo erectus, Neanderthal man.
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Answer: Australopithecus → Homo erectus → Neanderthal man → Cro-Magnon
2024 Q5(ii) Differentiate between Australopithecus and Modern man based on body hair.
Show Answer
Answer:
Australopithecus: Dense body hair
Modern man: Reduced body hair
2024 Q5(v)(a) Given schematic representation of inheritance of seed shape. Which is the dominant and recessive allele of the trait?
Show Answer
Answer:
Dominant: Round seed (R)
Recessive: Wrinkled seed (r)
2024 Q5(v)(b) What does the ratio 3 : 1 in the F2 generation represent?
Show Answer
Answer: Phenotypic ratio: 3 round seeds : 1 wrinkled seed
2024 Q5(v)(c) State Mendel's Law of Dominance.
Show Answer
Answer: In a pair of contrasting characters, one character is dominant over the other which remains recessive. In F1 generation, only the dominant character is expressed.
2025 Q1(v) A scientist wanted to conduct a genetic experiment on mice... What will be the phenotype of the offsprings?
Show Answer
Answer: All black offspring (if black is dominant over white)
2025 Q1(viii) Ajay and Vijay are siblings. Ajay can roll his tongue while Vijay cannot. What is the genotype of their parents?
Show Answer
Answer: Both parents heterozygous (Rr)
Explanation: For a recessive trait to appear, both parents must carry recessive allele.
2025 Q2(i)(e) Name an insect which is a classic example of natural selection due to industrial melanism.
Show Answer
Answer: Peppered moth (Biston betularia)
2025 Q3(iii) Mention the two pairs of nitrogenous bases that are present in a DNA strand and pair with each other by hydrogen bonds.
Show Answer
Answer: Adenine-Thymine (A-T), Guanine-Cytosine (G-C)
2025 Q4(i) What is the structure of DNA as proposed by Watson and Crick?
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Answer: Double helix structure with two antiparallel polynucleotide chains held together by hydrogen bonds between complementary base pairs (A-T, G-C).
2025 Q7(i) Define the term Allele.
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Answer: Alternative forms of a gene occupying the same locus on homologous chromosomes and controlling the same character.
2025 Q8(v)(a) Explain the phenotype of the offsprings of the F1 generation obtained from the initial cross (TTRR x ttrr).
Show Answer
Answer: All offspring will be tall with round seeds (phenotypically dominant for both traits).
2025 Q8(v)(b) Mention the phenotypic ratio of the F2 generation offsprings.
Show Answer
Answer: 9:3:3:1
9 Tall round : 3 Tall wrinkled : 3 Dwarf round : 1 Dwarf wrinkled
2025 Q8(v)(c) State Mendel's Law of Independent Assortment.
Show Answer
Answer: When two pairs of traits are combined in a hybrid, segregation of one pair of characters is independent of the other pair of characters.

Chapter 3: Plant Physiology (Photosynthesis, Absorption, Transpiration, Tropism)

Year Q No. Question
2017 Q1(a)(i) The process by which root hairs absorb water from the soil.
Show Answer
Answer: Osmosis
2017 Q1(c)(v) Rewrite the correct statement: The solvent used to dissolve the chlorophyll pigments while testing a leaf for starch is Soda lime.
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Answer: The solvent used to dissolve the chlorophyll pigments while testing a leaf for starch is alcohol.
2017 Q3(a)(i) What is the state of the cell shown in the diagram (plasmolysed)?
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Answer: Plasmolysed state
2017 Q3(a)(ii) Name the structure that acts as a selectively permeable membrane (in a plant cell).
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Answer: Plasma membrane
2017 Q3(a)(iii) Label the parts numbered 1 to 4 in the diagram (plasmolysed cell).
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Answer:
1. Cell wall
2. Plasma membrane
3. Cytoplasm
4. Hypertonic solution
2017 Q3(a)(iv) How can the above cell be brought back to its original condition? Mention the scientific term for the recovery of the cell.
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Answer: By placing in hypotonic solution (water).
Term: Deplasmolysis
2017 Q3(a)(v) State any two features of the above plant cell which is not present in animal cells.
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Answer:
1. Cell wall
2. Large central vacuole
2017 Q4(a)(i) Name the physiological process occurring in the green plant that has kept the mouse alive.
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Answer: Photosynthesis
2017 Q4(a)(ii) Explain the physiological process mentioned above.
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Answer: Photosynthesis is the process by which green plants use sunlight, carbon dioxide and water to synthesize glucose, releasing oxygen as a byproduct.
2017 Q4(a)(iii) Why did the mouse die in bell jar B?
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Answer: Because the plant was without chlorophyll (variegated leaves), so no photosynthesis occurred and oxygen was not released.
2017 Q4(a)(iv) What is the significance of the process as stated in (i) for life on earth.
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Answer: Photosynthesis:
1. Produces oxygen for respiration
2. Produces food (glucose) for all organisms
3. Maintains balance of oxygen and carbon dioxide in atmosphere
2017 Q4(a)(v) Represent the above mentioned physiological process in the form of a chemical equation.
Show Answer
Answer: 6CO₂ + 12H₂O → C₆H₁₂O₆ + 6O₂ + 6H₂O
2018 Q1(a)(v) Name The wax-like layer on the epidermis of leaves which reduces transpiration.
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Answer: Cuticle
2018 Q1(c)(i)-(v) Complete the paragraph by filling in the blanks (i) to (v) for the steps to test a leaf for starch.
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Answer:
(i) boiled in water
(ii) boiled in alcohol
(iii) water
(iv) iodine solution
(v) blue-black
2018 Q1(e)(iii) Correct the following statement: The cell sap of root hair is Hypotonic.
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Answer: The cell sap of root hair is hypertonic compared to soil water.
2018 Q1(e)(iv) Correct the following statement: Xylem transports starch from the leaves to all parts of the plant body.
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Answer: Phloem transports starch from the leaves to all parts of the plant body.
2018 Q2(b)(iv) Mention the exact location of Hydathodes.
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Answer: At the margins and tips of leaves
2018 Q3(b)(i) What aspect of photosynthesis is being tested in the above diagram (variegated leaf)?
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Answer: Chlorophyll is necessary for photosynthesis
2018 Q3(b)(iii) Why was the plant kept in the dark before beginning the experiment?
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Answer: To destarch the leaves (remove existing starch)
2018 Q3(b)(iv) What will be the result of the starch test performed on leaf 'A' shown in the diagram? Give an example of a plant with variegated leaves.
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Answer:
Result: Only green parts turn blue-black, white parts remain brown
Example: Coleus, Croton, Money plant
2018 Q5(b)(v) Differentiate between Hypotonic solution and Hypertonic solution (condition of a plant cell when placed in them).
Show Answer
Answer:
Hypotonic solution: Cell becomes turgid
Hypertonic solution: Cell becomes plasmolysed
2018 Q6(b)(iv) Biological explanation: Plants growing in fertilized soil are often found to wilt if the soil is not adequately watered.
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Answer: Fertilizers increase osmotic concentration of soil water, making it hypertonic. This causes plasmolysis of root hairs, reducing water absorption and causing wilting.
2018 Q7(a)(i) Name the physiological process depicted in the diagram (Potometer). Why was oil added to the water?
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Answer:
Process: Transpiration
Oil purpose: To prevent evaporation of water from the surface
2018 Q7(a)(ii) When placed in bright sunlight for four hours, what do you observe with regard to the initial and final weight of the plant? Give a suitable reason for your answer.
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Answer:
Observation: Final weight less than initial weight
Reason: Loss of water through transpiration exceeds water absorption
2018 Q7(a)(iii)(1) What happens to the level of water when this setup is placed in: Humid conditions?
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Answer: Water level falls slowly (less transpiration)
2018 Q7(a)(iii)(2) What happens to the level of water when this setup is placed in: Windy conditions?
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Answer: Water level falls quickly (more transpiration)
2018 Q7(a)(iv) Mention any three adaptations found in plants to overcome the process mentioned in (i).
Show Answer
Answer:
1. Thick cuticle
2. Sunken stomata
3. Reduced leaf surface
4. Leaf rolling
2018 Q7(a)(v) Explain the term 'Guttation'.
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Answer: The process of exudation of water droplets from the margins and tips of leaves through hydathodes, usually at night or early morning.
2019 Q1(c)(iii) Biological reason: Root hairs become flaccid and droop when excess fertilizers are added to the moist soil around them.
Show Answer
Answer: Fertilizers make soil solution hypertonic, causing plasmolysis of root hairs which lose water and become flaccid.
2019 Q1(e)(v) Which one of the following does not affect the rate of transpiration? (D. Age of the plant).
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Answer: D. Age of the plant
2019 Q1(g)(i) Expand the abbreviation – ABA.
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Answer: Abscisic Acid
2019 Q1(g)(ii) Expand the abbreviation – IAA.
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Answer: Indole Acetic Acid
2019 Q2(a)(i) Label the parts 1 and 2 (tropic movement diagram).
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Answer:
1. Shoot tip
2. Root tip
2019 Q2(a)(ii) Name the tropic movement shown by part 1.
Show Answer
Answer: Phototropism
2019 Q2(a)(iii) Part 1 is affected by two stimuli. Name them. Which one of the two is stronger?
Show Answer
Answer:
Stimuli: Light and gravity
Stronger: Light (in shoot tip)
2019 Q2(a)(iv) What is Thigmotropism? Give one example.
Show Answer
Answer:
Definition: Growth movement in response to touch
Example: Tendrils of pea plant coiling around support
2019 Q2(a)(v) What is meant by 'Positive' and 'Negative' tropic movements in plants?
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Answer:
Positive tropism: Movement towards the stimulus
Negative tropism: Movement away from the stimulus
2019 Q2(b)(iii) Mention the exact location of Thylakoids.
Show Answer
Answer: In the chloroplast, stacked to form grana
2019 Q3(a)(i) Name the factor studied in this experiment (Black paper clip).
Show Answer
Answer: Light is necessary for photosynthesis
2019 Q3(a)(ii) What will you observe in the experimental leaf after the starch test?
Show Answer
Answer: Covered part remains brown, uncovered part turns blue-black
2019 Q3(a)(iii) Explain the process of Photosynthesis.
Show Answer
Answer: Photosynthesis is the process by which green plants use sunlight, carbon dioxide and water to synthesize glucose, releasing oxygen as a byproduct.
2019 Q3(a)(iv) Give a balanced chemical equation to represent the process of photosynthesis.
Show Answer
Answer: 6CO₂ + 12H₂O → C₆H₁₂O₆ + 6O₂ + 6H₂O
2019 Q3(a)(v) Draw a neat, labelled diagram of an experimental setup to show that oxygen is released during photosynthesis.
Show Answer
Answer: Diagram showing:
1. Aquatic plant (Hydrilla)
2. Funnel inverted over plant
3. Test tube over funnel stem
4. Water in beaker
5. Bubbles of oxygen collecting in test tube
2019 Q3(b)(ii) State the main function of Cytokinins.
Show Answer
Answer: Promote cell division and delay senescence (aging)
2019 Q5(a)(i) Name the process being studied (Bell Jar setup). Define the process.
Show Answer
Answer:
Process: Transpiration
Definition: Loss of water in the form of water vapor from aerial parts of plants, mainly through stomata.
2019 Q5(a)(ii) Why was the pot enclosed in a rubber sheet?
Show Answer
Answer: To prevent evaporation of water from the soil surface
2019 Q5(a)(iii) Mention two external factors which can accelerate the above process.
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Answer:
1. High temperature
2. Low humidity
3. Wind
2019 Q5(a)(iv) List two adaptations in plants to reduce the above process.
Show Answer
Answer:
1. Thick cuticle
2. Sunken stomata
3. Reduced leaf surface
2019 Q5(a)(v) Draw a neat, labelled diagram of a stomatal apparatus.
Show Answer
Answer: Diagram showing:
1. Two guard cells
2. Stomatal pore
3. Chloroplasts in guard cells
4. Epidermal cells
5. Nucleus in guard cells
2020 Q1(a)(i) Name The process of transformation of several glucose molecules into one molecule of starch.
Show Answer
Answer: Polymerization
2020 Q1(b)(ii) Explain the term Diffusion.
Show Answer
Answer: Movement of molecules from a region of higher concentration to a region of lower concentration until evenly distributed.
2020 Q1(b)(iii) Explain the term Photolysis.
Show Answer
Answer: Splitting of water molecules into hydrogen and oxygen in the presence of light during photosynthesis.
2020 Q1(f)(i) Choose the ODD one out: Auxin, Ethylene, Adrenaline, Cytokinin. Name the category to which the others belong.
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Answer: Adrenaline is odd one out
Category: Others are plant hormones (phytohormones)
2020 Q1(g)(iv) Match Stroma with Light independent reaction/Light dependent reaction.
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Answer: Stroma → Light independent reaction (Dark reaction)
2020 Q1(g)(v) Match Stomata with diffusion of gases/chlorophyll.
Show Answer
Answer: Stomata → diffusion of gases
2020 Q1(h)(i) Name the tropic movement shown in the diagram (root/water).
Show Answer
Answer: Hydrotropism
2020 Q1(h)(ii) Explain the tropic movement mentioned in (i).
Show Answer
Answer: Growth movement of plant parts in response to water
2020 Q1(h)(iii) Label the part marked 'A'.
Show Answer
Answer: Root tip
2020 Q1(h)(iv) What is part A attracted to?
Show Answer
Answer: Water/moisture
2020 Q1(h)(v) Give an example of a plant which shows Thigmotropism.
Show Answer
Answer: Pea plant (tendrils)
2020 Q2(a)(i) Which factor is being studied here (Photosynthesis experiment)?
Show Answer
Answer: Carbon dioxide is necessary for photosynthesis
2020 Q2(a)(ii) What is the purpose of keeping KOH in the flask?
Show Answer
Answer: To absorb carbon dioxide from the air inside the flask
2020 Q2(a)(iii) Explain the term Photosynthesis.
Show Answer
Answer: Photosynthesis is the process by which green plants use sunlight, carbon dioxide and water to synthesize glucose, releasing oxygen as a byproduct.
2020 Q2(a)(iv) What will you observe when the leaf A is tested for starch?
Show Answer
Answer: Leaf A remains brown (no starch formed as CO₂ was absent)
2020 Q2(a)(v) Write a well balanced chemical equation for the process of photosynthesis.
Show Answer
Answer: 6CO₂ + 12H₂O → C₆H₁₂O₆ + 6O₂ + 6H₂O
2020 Q3(b)(i) Biological reason: It is advisable to keep green plants in an aquarium.
Show Answer
Answer: Green plants produce oxygen through photosynthesis, which is used by aquatic animals for respiration.
2020 Q4(b)(i) Differentiate between Transpiration and Guttation (place of occurrence).
Show Answer
Answer:
Transpiration: Occurs through stomata, lenticels and cuticle
Guttation: Occurs through hydathodes at leaf margins
2020 Q4(b)(iv) Differentiate between Osmosis and Active Transport (Substances undergoing movement).
Show Answer
Answer:
Osmosis: Only water molecules move
Active Transport: Both water and solute molecules can move
2020 Q5(a)(i) Will the level of mercury in the glass tubing rise or fall (Potometer)? Which conducting tissue of the plant does the glass-tubing represent?
Show Answer
Answer:
Mercury level: Rises (due to transpiration pull)
Tissue: Xylem vessels
2020 Q5(a)(ii) Define Transpiration.
Show Answer
Answer: Loss of water in the form of water vapor from aerial parts of plants, mainly through stomata.
2020 Q5(a)(iii)(1) How will the rate of the above process differ if the environment of the plant has: Less humidity?
Show Answer
Answer: Rate increases
2020 Q5(a)(iii)(2) How will the rate of the above process differ if the environment of the plant has: High temperature?
Show Answer
Answer: Rate increases
2020 Q5(a)(iv) State any two advantages of transpiration to the plant.
Show Answer
Answer:
1. Creates transpiration pull for ascent of sap
2. Cools the plant surface
3. Helps in mineral absorption and distribution
2020 Q5(a)(v) Draw a neat labelled diagram of a Plasmolysed cell.
Show Answer
Answer: Diagram showing:
1. Cell wall
2. Shrunken cytoplasm separated from cell wall
3. Plasma membrane
4. Hypertonic solution outside
2020 Q6(a)(ii) State two functions of Ethylene.
Show Answer
Answer:
1. Promotes fruit ripening
2. Promotes senescence (aging) of leaves and flowers
3. Stimulates abscission (leaf fall)
2023 Q1(iv) Deplasmolysis occurs when a plasmolysed cell is placed in: (b) Tap water.
Show Answer
Answer: b. Tap water (hypotonic solution)
2023 Q1(xi) The site of light reaction in the cells of a green leaf is: (b) Grana of chloroplast.
Show Answer
Answer: b. Grana of chloroplast
2023 Q1(xii) The paper used to demonstrate unequal transpiration in a dicot leaf is: (d) Cobalt chloride paper.
Show Answer
Answer: d. Cobalt chloride paper
2023 Q2(i)(d) Name The openings on the barks of trees through which transpiration occurs.
Show Answer
Answer: Lenticels
2023 Q2(i)(e) Name A gaseous plant hormone which promotes ripening of fruits.
Show Answer
Answer: Ethylene
2023 Q2(ii)(b) Arrange and rewrite the terms in each group in correct order: Xylem, Soil water, Cortical cells, Root hair.
Show Answer
Answer: Soil water → Root hair → Cortical cells → Xylem
2023 Q3(i) Write the overall chemical equation for photosynthesis.
Show Answer
Answer: 6CO₂ + 12H₂O → C₆H₁₂O₆ + 6O₂ + 6H₂O
2023 Q3(iv) Excessive use of fertilizers in agricultural fields reduces the yield of crops. Justify the statement.
Show Answer
Answer: Excessive fertilizers make soil solution hypertonic, causing plasmolysis of root hairs. This reduces water absorption, leading to wilting and reduced yield.
2023 Q3(v)(a) Name the phenomenon depicted by the shoot in the diagram (bending towards light).
Show Answer
Answer: Phototropism
2023 Q3(v)(b) Which plant hormone plays an important role in the above movement?
Show Answer
Answer: Auxin (IAA)
2023 Q3(v)(c) Complete and rewrite: Shoots show positive _________ whereas, roots show positive __________.
Show Answer
Answer: Shoots show positive phototropism whereas, roots show positive geotropism.
2023 Q4(ii) What is Active transport?
Show Answer
Answer: Movement of molecules against concentration gradient using energy (ATP).
2023 Q6(i) Define the term Transpiration.
Show Answer
Answer: Loss of water in the form of water vapor from aerial parts of plants, mainly through stomata.
2023 Q6(ii) State any two adaptations in plants to reduce transpiration.
Show Answer
Answer:
1. Thick cuticle
2. Sunken stomata
3. Reduced leaf surface (spines)
4. Leaf rolling
2023 Q7(v)(a) Potted plant with variegated leaves... Which aspect of photosynthesis is being tested in the above diagram?
Show Answer
Answer: Chlorophyll is necessary for photosynthesis
2023 Q7(v)(b) Why was the plant kept in dark for 24 hours?
Show Answer
Answer: To destarch the leaves (remove existing starch)
2023 Q7(v)(c) After the starch test what will be the colour of the yellow and green parts of the leaf? Give reasons to support your answer.
Show Answer
Answer:
Yellow parts: Remain brown (no chlorophyll, no photosynthesis)
Green parts: Turn blue-black (chlorophyll present, photosynthesis occurs)
2023 Q8(iii) Leaves of certain plants roll up on a hot sunny day. Explain by giving suitable reasons.
Show Answer
Answer: To reduce transpiration by:
1. Reducing exposed surface area
2. Trapping moist air inside rolled leaf
3. Reducing direct sunlight exposure
2023 Q8(iv) What is a semi permeable membrane? Name the semi permeable membrane present in a plant cell.
Show Answer
Answer:
Definition: Membrane that allows only certain molecules to pass through
Name: Plasma membrane
2024 Q1(ii) The process of conversion of ADP to ATP during photosynthesis is called: (c) Photophosphorylation.
Show Answer
Answer: c. Photophosphorylation
2024 Q1(iii) The process in which water is lost from the margins of strawberry leaves is: (d) Guttation.
Show Answer
Answer: d. Guttation
2024 Q1(v) Which one of the following helps in the opening of stomata: (b) Potassium ions.
Show Answer
Answer: b. Potassium ions
2024 Q2(i)(a) Name Unicellular outgrowths from the epidermis of roots.
Show Answer
Answer: Root hairs
2024 Q2(i)(c) Name The tropic movement of plant parts in response to chemicals.
Show Answer
Answer: Chemotropism
2024 Q2(ii)(e) Arrange and rewrite the terms in each group in the correct order: Water vapour, Soil water, Leaves, Ascent of Sap.
Show Answer
Answer: Soil water → Ascent of Sap → Leaves → Water vapour
2024 Q2(iii)(a-e) Study the diagram... and fill in the blanks regarding experiment proving carbon dioxide is necessary for photosynthesis.
Show Answer
Answer:
(a) Potassium hydroxide (KOH)
(b) To absorb carbon dioxide
(c) No starch formed
(d) Starch formed
(e) Carbon dioxide is necessary for photosynthesis
2024 Q3(i) Expand the abbreviation-NADP.
Show Answer
Answer: Nicotinamide Adenine Dinucleotide Phosphate
2024 Q3(ii) Mention two adaptations in roots for absorption of water from the soil.
Show Answer
Answer:
1. Numerous root hairs increase surface area
2. Thin cell walls of root hairs
3. Cell sap hypertonic compared to soil water
2024 Q3(v)(a) Name the phenomenon depicted by the shoot in the given figure.
Show Answer
Answer: Phototropism
2024 Q3(v)(b) Define the above phenomenon (tropism).
Show Answer
Answer: Growth movement of plant parts in response to external stimuli (light in this case).
2024 Q3(v)(c) Write the name of the part marked X.
Show Answer
Answer: Shoot tip
2024 Q4(iii) Mention two advantages of Transpiration.
Show Answer
Answer:
1. Creates transpiration pull for ascent of sap
2. Cools the plant surface
3. Helps in mineral absorption and distribution
2024 Q6(v) Draw a neat, labelled diagram of a chloroplast.
Show Answer
Answer: Diagram showing:
1. Double membrane
2. Grana (stacks of thylakoids)
3. Stroma
4. Lamellae
5. DNA and ribosomes in stroma
2024 Q7(iv) Write any two limitations of using a Ganong's Potometer to demonstrate the uptake of water.
Show Answer
Answer:
1. Measures rate of water absorption, not transpiration directly
2. Cutting the plant may introduce air bubbles in xylem
3. Difficult to maintain airtight connections
2025 Q1(vi) Assertion/Reason: A turgid plant cell is in a balanced state... In a turgid cell, turgor pressure and wall pressure are equal...
Show Answer
Answer: Both Assertion and Reason are true and Reason is the correct explanation of Assertion.
2025 Q1(vii) The optimum temperature for photosynthesis is: (d) 25 – 35oC.
Show Answer
Answer: d. 25 – 35°C
2025 Q1(xiv) Identify the correct pair matching Tropism and Stimulus: P: Thigmotropism/Touch, R: Chemotropism/Chemicals.
Show Answer
Answer: P and R are correct
2025 Q2(i)(b) Name A waxy layer on the upper epidermis of leaves meant to reduce Transpiration.
Show Answer
Answer: Cuticle
2025 Q2(iv)(e) Name the structure: Regulation of the opening and closing of stomata.
Show Answer
Answer: Guard cells
2025 Q3(i) Write the overall chemical equation for photosynthesis.
Show Answer
Answer: 6CO₂ + 12H₂O → C₆H₁₂O₆ + 6O₂ + 6H₂O
2025 Q3(ii)(a) Name the phytohormone that Ramesh sprays to improve the shape of the grapes.
Show Answer
Answer: Gibberellin
2025 Q3(ii)(b) What is the technical term for the formation of seedless grapes?
Show Answer
Answer: Parthenocarpy
2025 Q4(v) Given below is a picture of a tree. Mention the scientific phenomena occurring in the parts labelled (a), (b) and (c).
Show Answer
Answer:
(a) Roots: Absorption of water and minerals
(b) Stem/Leaves: Photosynthesis
(c) Leaves: Transpiration
2025 Q5(v) Draw a neat, labelled diagram to show that oxygen is released during photosynthesis.
Show Answer
Answer: Diagram showing:
1. Aquatic plant (Hydrilla)
2. Funnel inverted over plant
3. Test tube over funnel stem
4. Water in beaker
5. Bubbles of oxygen collecting in test tube
2025 Q6(i) Where are Hydathodes located?
Show Answer
Answer: At the margins and tips of leaves
2025 Q6(v) Copy the diagram (plasmolysed cortical cell) and label the following parts: Cytoplasm, Hypertonic solution, Plasma membrane.
Show Answer
Answer: Diagram showing:
1. Cell wall
2. Shrunken cytoplasm
3. Plasma membrane (separated from cell wall)
4. Hypertonic solution outside cell

Chapter 4: Human Anatomy & Physiology

Sub-Chapter 4A: Circulation, Blood, and Immunity

Year Q No. Question
2017 Q1(b)(ii) Penicillin obtained from a fungus is: A. Antibiotic, B. Antiseptic, C. Antibody, D. Antiserum.
Show Answer
Answer: A. Antibiotic
2017 Q1(d)(i) Rewrite the terms in correct order in a logical sequence: Fibrin, Platelets, Thromboplastin, Fibrinogen, Thrombin.
Show Answer
Answer: Platelets → Thromboplastin → Fibrinogen → Thrombin → Fibrin
2017 Q1(f)(iv) Complete the second pair on a similar basis: Foetus : Amnion : : Heart : ____________.
Show Answer
Answer: Pericardium
2017 Q1(g)(v) Match Diabetes mellitus with Hyperglycemia/Hypoglycemia.
Show Answer
Answer: Diabetes mellitus → Hyperglycemia
2017 Q2(b)(iii) Differentiate between Antibiotic and Antibody [Source].
Show Answer
Answer:
Antibiotic: Obtained from microorganisms (fungi/bacteria)
Antibody: Produced by lymphocytes in body
2017 Q5(b)(v) Biological reason: The left ventricle of the heart has a thicker wall than the right ventricle.
Show Answer
Answer: Because left ventricle pumps blood to entire body (systemic circulation) requiring more force, while right ventricle pumps only to lungs (pulmonary circulation).
2017 Q6(a)(i) Which parts of heart are in the diastolic phase? Give a reason to support your answer.
Show Answer
Answer:
Parts: Atria and ventricles both in diastole
Reason: AV valves open, blood flowing from atria to ventricles
2017 Q6(a)(ii) Label the parts numbered 1 and 2 in the diagram (heart). What type of blood flows through them?
Show Answer
Answer:
1. Pulmonary artery - Deoxygenated blood
2. Aorta - Oxygenated blood
Note: Based on typical heart diagram
2017 Q6(a)(iii) What causes the heart sounds 'LUBB' and 'DUP'?
Show Answer
Answer:
LUBB: Closure of atrioventricular valves (tricuspid and bicuspid)
DUP: Closure of semilunar valves (aortic and pulmonary)
2017 Q6(a)(iv) Name the blood vessels that supply oxygenated blood to the heart muscles.
Show Answer
Answer: Coronary arteries
2017 Q6(a)(v) Draw neat labelled diagrams of a cross section of an artery and a vein.
Show Answer
Answer:
Artery: Thick muscular wall, small lumen, no valves
Vein: Thin muscular wall, large lumen, valves present
2017 Q6(b)(i) Give appropriate biological / technical terms for The type of immunity that exists in our body due to our genetic makeup.
Show Answer
Answer: Innate immunity
2017 Q6(b)(vii) Give appropriate biological / technical terms for The mild chemical substance which when applied on the body kills germs.
Show Answer
Answer: Antiseptic
2017 Q6(b)(x) Give appropriate biological / technical terms for Cellular components of blood containing haemoglobin.
Show Answer
Answer: Erythrocytes (Red Blood Cells)
2018 Q1(a)(i) Name The organization which procures and supplies blood during an emergency.
Show Answer
Answer: Red Cross Society
2018 Q1(a)(ii) The blood vessel which supplies blood to the liver.
Show Answer
Answer: Hepatic artery
2018 Q1(d) Match Adrenal virilism with Hypersecretion of adrenal cortex/Hyposecretion of adrenal cortex.
Show Answer
Answer: Adrenal virilism → Hypersecretion of adrenal cortex
2018 Q1(f)(v) Choose between the two options: Blood in the pulmonary artery or pulmonary vein (Which one contains less oxyhaemoglobin?).
Show Answer
Answer: Pulmonary artery contains less oxyhaemoglobin (deoxygenated blood)
2018 Q4(b)(vii) Technical term for Squeezing out of white blood cells from the capillaries into the surrounding tissues.
Show Answer
Answer: Diapedesis
2018 Q4(b)(ix) Technical term for The relaxation phase of the heart.
Show Answer
Answer: Diastole
2018 Q6(a)(i) Name the components numbered '1' to '4' (blood smear).
Show Answer
Answer:
1. Red Blood Cell (Erythrocyte)
2. White Blood Cell (Leucocyte)
3. Platelet (Thrombocyte)
4. Plasma
2018 Q6(a)(ii) Mention two structural differences between the parts '1' (RBC) and '2' (WBC).
Show Answer
Answer:
1. RBC: Biconcave disc shape; WBC: Irregular/amoeboid shape
2. RBC: No nucleus; WBC: Has nucleus
3. RBC: Contains haemoglobin; WBC: No haemoglobin
2018 Q6(a)(iii) Name the soluble protein found in part '4' which forms insoluble threads during clotting of blood.
Show Answer
Answer: Fibrinogen
2018 Q6(a)(iv) What is the average lifespan of the component numbered '1' (RBC)?
Show Answer
Answer: 120 days
2018 Q6(a)(v) Component numbered '1' do not have certain organelles but are very efficient in their function. Explain.
Show Answer
Answer: RBCs lack nucleus and mitochondria:
1. No nucleus: More space for haemoglobin, increasing oxygen carrying capacity
2. No mitochondria: Don't use oxygen for respiration, so all oxygen carried is delivered to tissues
2019 Q1(a)(v) Name The compound formed when haemoglobin combines with carbon dioxide in blood.
Show Answer
Answer: Carbaminohaemoglobin
2019 Q1(d)(iii) Match Acetylcholine with Neurotransmitter.
Show Answer
Answer: Acetylcholine → Neurotransmitter
2019 Q1(e)(i) While recording the pulse rate, where exactly does a doctor press on our wrist? (C. Artery).
Show Answer
Answer: C. Artery
2019 Q1(e)(iii) A muscular wall is absent in: (A. Capillary).
Show Answer
Answer: A. Capillary
2019 Q1(f)(i) Choose the ODD one out: Addison's disease, Cushing's Syndrome, Acromegaly, Leukemia. Name the category to which the others belong.
Show Answer
Answer: Leukemia is odd one out
Category: Others are hormonal disorders
2019 Q3(b)(iv) State the main function of the Coronary Artery.
Show Answer
Answer: Supplies oxygenated blood to heart muscles
2020 Q1(a)(iii) Name The iron containing pigment in erythrocytes.
Show Answer
Answer: Haemoglobin
2020 Q1(c)(ii) Complete the second pair on a similar basis: Brain : Meninges :: Heart : ___________.
Show Answer
Answer: Pericardium
2020 Q1(e)(ii) Agranulocytes are: (A. Lymphocytes, Monocytes).
Show Answer
Answer: A. Lymphocytes, Monocytes
2020 Q2(b)(i) Name the blood vessels labelled 1 to 4 (circulation pathway).
Show Answer
Answer:
1. Aorta
2. Pulmonary artery
3. Pulmonary vein
4. Vena cava
Note: Based on typical circulation diagram
2020 Q2(b)(ii) Which blood vessel supplies oxygenated blood to the muscles of the heart?
Show Answer
Answer: Coronary arteries
2020 Q2(b)(iii) What is the importance of blood vessel labelled 5?
Show Answer
Answer: Hepatic portal vein - carries blood from digestive organs to liver for processing of nutrients.
2020 Q2(b)(iv) What is the type of blood circulation that takes place between the heart and the lungs?
Show Answer
Answer: Pulmonary circulation
2020 Q2(b)(v) Draw a diagram of the different blood cells as seen in a smear of human blood.
Show Answer
Answer: Diagram showing:
1. Red Blood Cells (biconcave discs, no nucleus)
2. White Blood Cells (larger, with nucleus, irregular shape)
3. Platelets (small fragments)
2020 Q5(b)(viii) Give the technical term for Process by which leucocytes migrate through the walls of capillaries.
Show Answer
Answer: Diapedesis
2023 Q1(iii) The heart sound 'Dup' is produced when: (c) Semilunar valves close.
Show Answer
Answer: c. Semilunar valves close
2023 Q1(vii) The life span of an RBC is: (a) 120 days.
Show Answer
Answer: a. 120 days
2023 Q1(xiv) Oxygenated blood to liver is supplied by: (a) Hepatic artery.
Show Answer
Answer: a. Hepatic artery
2023 Q3(ii) Mention any two functions of blood.
Show Answer
Answer:
1. Transport of oxygen, nutrients, hormones
2. Removal of waste products (CO₂, urea)
3. Defense against pathogens
4. Regulation of body temperature
2023 Q8(v)(a) The diagram below depicts the human heart. Which part of the heart is in the contraction phase?
Show Answer
Answer: Ventricles (if AV valves closed, semilunar valves open)
2023 Q8(v)(b) Give a suitable reason to justify your answer in (a).
Show Answer
Answer: Because blood is being pumped out through arteries (aorta/pulmonary artery)
2023 Q8(v)(c) Distinguish between Systole and Diastole.
Show Answer
Answer:
Systole: Contraction phase of heart chambers
Diastole: Relaxation phase of heart chambers
2024 Q1(viii) If a person has a heart attack, what must be done immediately? P, Q, R, S options.
Show Answer
Answer: R. Cardiopulmonary resuscitation (CPR)
2024 Q1(xi) Osmosis takes place when there is: (c) A selectively permeable membrane.
Show Answer
Answer: c. A selectively permeable membrane
2024 Q2(iv)(a) Choose the odd one out: Prothrombin, Thrombin, Fibrinogen, Albumin. Name the category to which the others belong.
Show Answer
Answer: Albumin is odd one out
Category: Others are proteins involved in blood clotting
2024 Q2(iv)(c) Choose the odd one out: Neutrophils, Basophils, Monocytes, Eosinophils. Name the category to which the others belong.
Show Answer
Answer: Monocytes is odd one out
Category: Others are granulocytes (have granules in cytoplasm)
2024 Q5(iv)(a) Give the exact location of Pericardium.
Show Answer
Answer: Around the heart
2024 Q5(iv)(b) Give the exact location of Bicuspid valve.
Show Answer
Answer: Between left atrium and left ventricle
2024 Q6(i) Define the term-Diapedesis.
Show Answer
Answer: Process by which white blood cells squeeze through capillary walls to reach site of infection.
2024 Q6(iii) Carbon monoxide is dangerous when inhaled in excess. Comment on the statement.
Show Answer
Answer: Carbon monoxide binds with haemoglobin more strongly than oxygen, forming carboxyhaemoglobin. This reduces oxygen carrying capacity of blood, causing oxygen deficiency in tissues.
2024 Q7(iii) Mention two structural differences between an artery and a vein.
Show Answer
Answer:
1. Artery: Thick muscular wall; Vein: Thin muscular wall
2. Artery: Narrow lumen; Vein: Wide lumen
3. Artery: No valves; Vein: Has valves
2024 Q8(ii)(a) Name the mineral element required for Clotting of blood.
Show Answer
Answer: Calcium
2024 Q8(iv) Why are RBCs efficient in their functions though they lack nucleus and mitochondria?
Show Answer
Answer:
1. No nucleus: More space for haemoglobin, increasing oxygen carrying capacity
2. No mitochondria: Don't use oxygen for respiration, so all oxygen carried is delivered to tissues
3. Biconcave shape: Increases surface area for gas exchange
2025 Q2(ii)(a) The heart is enclosed by a membrane called (a) ____________.
Show Answer
Answer: (a) Pericardium
2025 Q2(ii)(b) The ventricles give rise to two large blood vessels called (b) ____________ and (c) ____________.
Show Answer
Answer: (b) Aorta, (c) Pulmonary artery
2025 Q2(ii)(d) The flaps of the cuspid valves are kept in position by (d) ____________.
Show Answer
Answer: (d) Chordae tendineae
2025 Q2(ii)(e) (e) ____________ arteries supply oxygenated blood to the walls of the heart.
Show Answer
Answer: (e) Coronary
2025 Q4(ii)(a) Name the white blood cells that show phagocytosis.
Show Answer
Answer: Neutrophils, Monocytes
2025 Q4(ii)(b) Name the white blood cells that produce antibodies.
Show Answer
Answer: Lymphocytes
2025 Q7(v)(c) Which part of the autonomic nervous system increases the secretion of Adrenaline?
Show Answer
Answer: Sympathetic nervous system

Sub-Chapter 4B: Excretory System

Year Q No. Question
2017 Q1(a)(ii) Name The organ which produces urea.
Show Answer
Answer: Liver
2017 Q1(b)(iv) Surgical method of sterilization in a woman involves cutting and tying of: D. Oviduct. (Often contrasted with Ureter/Urethra).
Show Answer
Answer: D. Oviduct
2017 Q1(e)(v) Choose the ODD one out: Bile, Urea, Uric acid, Ammonia. Name the CATEGORY to which the others belong.
Show Answer
Answer: Bile is odd one out
Category: Others are nitrogenous wastes
2017 Q2(b)(iv) Differentiate between Renal cortex and Renal medulla [Parts of the nephrons present].
Show Answer
Answer:
Renal cortex: Contains Bowman's capsules and convoluted tubules
Renal medulla: Contains loops of Henle and collecting ducts
2017 Q5(b)(iv) Biological reason: There is frequent urination in winter than in summer.
Show Answer
Answer: In winter, less sweating occurs, so more water is eliminated through urine. Also, vasoconstriction reduces blood flow to skin, increasing blood volume and thus urine production.
2018 Q1(e)(i) Correct the following statement: Normal pale yellow colour of the urine is due to the presence of the pigment Melanin.
Show Answer
Answer: Normal pale yellow colour of the urine is due to the presence of the pigment Urochrome.
2018 Q1(f)(i) Choose between the two options: Blood in the renal artery or renal vein (Which one has more urea?).
Show Answer
Answer: Renal artery has more urea
2018 Q4(b)(i) Technical term for Process of maintaining water and salt balance in the blood.
Show Answer
Answer: Osmoregulation
2018 Q5(a)(i) Name the structure represented in the diagram (Nephron part).
Show Answer
Answer: Bowman's capsule
2018 Q5(a)(ii) What is the liquid entering part '1' called? Name two substances present in this liquid that are reabsorbed in the tubule.
Show Answer
Answer:
Liquid: Glomerular filtrate
Substances: Glucose, amino acids, water, salts
2018 Q5(a)(iii) What is the fluid that comes to part '2' called? Name the main nitrogenous waste in it.
Show Answer
Answer:
Fluid: Urine
Nitrogenous waste: Urea
2018 Q5(a)(iv) Mention the three main steps involved in the formation of the fluid mentioned in (iii) above.
Show Answer
Answer:
1. Ultrafiltration (in Bowman's capsule)
2. Selective reabsorption (in tubules)
3. Tubular secretion (in tubules)
2018 Q5(a)(v) Name the substance which may be present in the fluid in part '2' if a person suffers from Diabetes mellitus.
Show Answer
Answer: Glucose
2018 Q5(b)(iv) Differentiate between Ureter and Urethra [function].
Show Answer
Answer:
Ureter: Carries urine from kidney to urinary bladder
Urethra: Carries urine from urinary bladder to outside
2019 Q1(b)(iv) Correct and rewrite the statement: The kidney is composed of number of neurons.
Show Answer
Answer: The kidney is composed of number of nephrons.
2019 Q4(a)(i) Identify the system (Urinary system).
Show Answer
Answer: Urinary/Excretory system
2019 Q4(a)(ii) Label the parts marked 2 and 4 (Urinary system). Mention the function of part 5.
Show Answer
Answer:
2. Ureter
4. Urethra
5. Urinary bladder: Stores urine temporarily
2019 Q4(a)(iii) Name the structural and functional units of the part marked 1 (Kidney).
Show Answer
Answer: Nephron
2019 Q4(a)(iv) What is the fluid that accumulates in part 3? Which is the main nitrogenous waste present in it?
Show Answer
Answer:
Fluid: Urine
Nitrogenous waste: Urea
2019 Q4(a)(v) Draw a neat, labelled diagram of the longitudinal section of part 1 (Kidney).
Show Answer
Answer: Diagram showing:
1. Cortex (outer region)
2. Medulla (inner region with pyramids)
3. Pelvis (funnel-shaped)
4. Ureter
5. Renal artery and vein
2020 Q1(a)(iv) Name The duct which transports urine from the kidney to the urinary bladder.
Show Answer
Answer: Ureter
2020 Q1(e)(iv) The structural and functional units of excretion in the human kidney is the: (D. Nephron).
Show Answer
Answer: D. Nephron
2020 Q4(a)(i) In which region of the kidney is the above structure present (Nephron)?
Show Answer
Answer: Renal cortex
2020 Q4(a)(ii) Label the parts numbered 1 to 4 (Nephron).
Show Answer
Answer:
1. Afferent arteriole
2. Efferent arteriole
3. Bowman's capsule
4. Glomerulus
2020 Q4(a)(iii) What is the technical term for the process that occurs in part 3 (Bowman's capsule)?
Show Answer
Answer: Ultrafiltration
2020 Q4(a)(iv) Why is fluid X (Glomerular filtrate) not called urine? Justify your answer.
Show Answer
Answer: Because glomerular filtrate contains useful substances like glucose, amino acids, salts, and water that need to be reabsorbed. Urine is the final product after selective reabsorption and tubular secretion.
2020 Q4(a)(v) Draw a neat, labelled diagram of the urinary system of man.
Show Answer
Answer: Diagram showing:
1. Two kidneys
2. Two ureters
3. Urinary bladder
4. Urethra
2023 Q1(ix) The pale yellow colour of normal human urine is due to the pigment: (c) Urochrome.
Show Answer
Answer: c. Urochrome
2023 Q2(iv)(c) Choose the odd one out: Uterus, Urethra, Urinary bladder, Ureter. Name the category to which the others belong.
Show Answer
Answer: Uterus is odd one out
Category: Others are parts of urinary system
2023 Q6(v) Draw a neat, labelled diagram of a Malpighian Capsule.
Show Answer
Answer: Diagram showing:
1. Bowman's capsule (cup-shaped)
2. Glomerulus (capillary network)
3. Afferent arteriole
4. Efferent arteriole
2023 Q7(ii) Renal cortex has a dotted appearance and Renal medulla has a striped appearance. Explain.
Show Answer
Answer:
Renal cortex: Dotted due to presence of numerous Bowman's capsules
Renal medulla: Striped due to parallel arrangement of loops of Henle and collecting ducts
2024 Q1(iv) The hormone that affects urination is: (b) Vasopressin.
Show Answer
Answer: b. Vasopressin (ADH - Antidiuretic Hormone)
2024 Q2(i)(d) Name The main nitrogenous waste formed in the body.
Show Answer
Answer: Urea
2024 Q2(ii)(d) Arrange and rewrite the terms in each group in the correct order: Loop of Henle, Distal convoluted tubule, Bowman's Capsule, Proximal convoluted tubule.
Show Answer
Answer: Bowman's Capsule → Proximal convoluted tubule → Loop of Henle → Distal convoluted tubule
2024 Q3(iii) Differentiate between Afferent arteriole and Efferent arteriole (diameter).
Show Answer
Answer:
Afferent arteriole: Wider diameter
Efferent arteriole: Narrower diameter
Function: Creates high pressure in glomerulus for ultrafiltration
2024 Q8(i) Define the term ultrafiltration.
Show Answer
Answer: Filtration under pressure in glomerulus where small molecules like water, glucose, amino acids, salts, and urea pass through glomerular membrane into Bowman's capsule, leaving large molecules like proteins and blood cells behind.
2025 Q5(i) What is Micturition? Explain.
Show Answer
Answer: The process of expelling urine from the urinary bladder through urethra. It is a reflex action controlled by spinal cord, but can be voluntarily inhibited.
2025 Q8(i) Explain the term Excretion.
Show Answer
Answer: The process of elimination of metabolic waste products from the body to maintain homeostasis.

Chapter 5: Reproductive System & Human Development

Year Q No. Question
2017 Q1(b)(iv) Surgical method of sterilization in a woman involves cutting and tying of: D. Oviduct.
Show Answer
Answer: D. Oviduct (Fallopian tube)
2017 Q5(a)(i) Label the parts numbered 1 to 3 in the diagram (LS of testis).
Show Answer
Answer:
1. Seminiferous tubules
2. Epididymis
3. Vas deferens (Sperm duct)
2017 Q5(a)(ii) In which part of the testis are the sperms produced?
Show Answer
Answer: Seminiferous tubules
2017 Q5(a)(iii) State the functions of the parts labelled 1 and 3 (testis diagram).
Show Answer
Answer:
1 (Seminiferous tubules): Produce sperms
3 (Vas deferens): Transports sperms from epididymis to urethra
2017 Q5(a)(iv) Name the cells that secrete Testosterone.
Show Answer
Answer: Leydig cells (Interstitial cells)
2017 Q5(a)(v) Draw a neat, labelled diagram of a sperm.
Show Answer
Answer: Diagram showing:
1. Head (with acrosome and nucleus)
2. Middle piece (with mitochondria)
3. Tail (flagellum for movement)
2017 Q6(b)(iii) Give appropriate biological / technical terms for The accessory gland in human males whose secretion activates the sperms.
Show Answer
Answer: Prostate gland
2017 Q6(b)(v) Give appropriate biological / technical terms for The kind of twins formed from two fertilised eggs.
Show Answer
Answer: Fraternal twins (Dizygotic twins)
2018 Q2(b)(i) Mention the exact location of Epididymis.
Show Answer
Answer: On the posterior surface of each testis
2018 Q3(a)(i) Arrange the letters given below each diagram in a logical sequence to show the correct order in the process of fertilisation of an egg.
Show Answer
Answer: Ovulation → Fertilization → Zygote formation → Cleavage → Morula → Blastocyst → Implantation
2018 Q3(a)(ii) Where does fertilisation normally take place? What is 'Implantation' that follows fertilisation?
Show Answer
Answer:
Fertilization site: Fallopian tube (oviduct)
Implantation: Attachment of blastocyst to uterine wall
2018 Q3(a)(iii) Mention the chromosome number of the egg and zygote in humans.
Show Answer
Answer:
Egg: 23 chromosomes (haploid)
Zygote: 46 chromosomes (diploid)
2018 Q3(a)(iv) Explain the term 'Gestation'. How long does Gestation last in humans?
Show Answer
Answer:
Gestation: Period of development from fertilization to birth
Duration: Approximately 280 days (9 months)
2018 Q3(a)(v) Draw a neat, labelled diagram of a mature human sperm.
Show Answer
Answer: Diagram showing:
1. Head (with acrosome and nucleus)
2. Middle piece (with mitochondria)
3. Tail (flagellum for movement)
2018 Q4(b)(vi) Technical term for The onset of menstruation in a young girl.
Show Answer
Answer: Menarche
2018 Q4(b)(viii) Technical term for The fluid which surrounds the foetus.
Show Answer
Answer: Amniotic fluid
2018 Q5(b)(iii) Differentiate between Testosterone and Oestrogen [organ which secretes].
Show Answer
Answer:
Testosterone: Secreted by testes (Leydig cells)
Oestrogen: Secreted by ovaries
2018 Q6(b)(ii) Biological explanation: The placenta is an important structure for the development of a foetus.
Show Answer
Answer: Placenta allows exchange of nutrients, oxygen, antibodies from mother to foetus and removal of waste products from foetus to mother. It also produces hormones like progesterone to maintain pregnancy.
2019 Q1(a)(iii) The structure which connects the placenta and the foetus.
Show Answer
Answer: Umbilical cord
2019 Q1(b)(ii) Correct and rewrite the statement: The protective sac which develops around the developing embryo is called the Pericardium.
Show Answer
Answer: The protective sac which develops around the developing embryo is called the Amnion.
2019 Q1(d)(ii) Match Leydig cells with Testosterone.
Show Answer
Answer: Leydig cells → Testosterone
2019 Q1(e)(ii) In a human male, a sperm will contain: (D. Either X or Y chromosome).
Show Answer
Answer: D. Either X or Y chromosome
2019 Q1(e)(iv) On which day of the menstrual cycle does ovulation take place? (C. 14th day).
Show Answer
Answer: C. 14th day
2019 Q2(b)(iv) Mention the exact location of Amniotic fluid.
Show Answer
Answer: Within the amniotic sac (between amnion and embryo)
2019 Q3(b)(v) State the main function of Seminal Vesicles.
Show Answer
Answer: Secrete alkaline fluid containing fructose that provides energy to sperms and forms part of semen.
2019 Q7(b)(iv) Mention the number and the name of the part involved in fertilization and implantation from the diagram (female reproductive system).
Show Answer
Answer:
Fertilization: Fallopian tube (oviduct)
Implantation: Uterus
2019 Q7(b)(v)(1) Mention the surgical methods of contraception in: Human males.
Show Answer
Answer: Vasectomy
2019 Q7(b)(v)(2) Mention the surgical methods of contraception in: Human females.
Show Answer
Answer: Tubectomy
2020 Q1(c)(v) Complete the second pair on a similar basis: Uterus : Implantation :: Fallopian tube : __________.
Show Answer
Answer: Fertilization
2020 Q1(e)(i) The fusion of the sperm and ovum is termed as: (C. Fertilization).
Show Answer
Answer: C. Fertilization
2020 Q1(e)(v) In a human female, ovum consists of: (D. 22 autosomes and 1 X-chromosome).
Show Answer
Answer: D. 22 autosomes and 1 X-chromosome
2020 Q1(f)(v) Choose the ODD one out: Prostate gland, Cowper's gland, seminal vesicle, seminiferous tubules. Name the category to which the others belong.
Show Answer
Answer: Seminiferous tubules is odd one out
Category: Others are accessory glands
2020 Q5(b)(iv) Give the technical term for The accessory gland in human males whose secretion neutralises the acid in the vagina.
Show Answer
Answer: Prostate gland
2020 Q5(b)(vii) Give the technical term for A surgical method of fertility control in human males.
Show Answer
Answer: Vasectomy
2020 Q6(a)(iv) State two functions of Testis.
Show Answer
Answer:
1. Production of sperms (in seminiferous tubules)
2. Secretion of testosterone (by Leydig cells)
2020 Q7(b)(i) Label the parts numbered 1 to 3 in the diagram (developing human foetus).
Show Answer
Answer:
1. Umbilical cord
2. Placenta
3. Amniotic sac
2020 Q7(b)(ii) Mention any two functions of the part labelled 2 (Placenta) in the diagram.
Show Answer
Answer:
1. Exchange of nutrients, oxygen, and waste products between mother and foetus
2. Production of hormones (progesterone, estrogen, HCG) to maintain pregnancy
2020 Q7(b)(iii) Explain the significance of the part numbered 3 (Umbilical cord) in the diagram.
Show Answer
Answer: Umbilical cord contains blood vessels (one vein carrying oxygenated blood and nutrients from placenta to foetus, and two arteries carrying deoxygenated blood and wastes from foetus to placenta).
2020 Q7(b)(iv) Define the term 'Gestation'. What is the normal gestational period of the developing embryo?
Show Answer
Answer:
Gestation: Period of development from fertilization to birth
Period: Approximately 280 days (9 months)
2020 Q7(b)(v) Mention the sex chromosomes in a male and female embryo.
Show Answer
Answer:
Male embryo: XY
Female embryo: XX
2023 Q1(i) The sex chromosome in a human ovum is: (a) X chromosome.
Show Answer
Answer: a. X chromosome
2023 Q2(i)(c) Name The permanent stoppage of menstruation in human females around the age of 45 years. (Menopause).
Show Answer
Answer: Menopause
2023 Q2(ii)(e) Arrange and rewrite the terms in each group in correct order: Testis, Urethra, Sperm duct, Epididymis.
Show Answer
Answer: Testis → Epididymis → Sperm duct (Vas deferens) → Urethra
2023 Q2(v)(c) State the exact location of Amniotic fluid.
Show Answer
Answer: Within the amniotic sac (between amnion and embryo)
2023 Q4(v) Draw a neat, labelled diagram of a human sperm.
Show Answer
Answer: Diagram showing:
1. Head (with acrosome and nucleus)
2. Middle piece (with mitochondria)
3. Tail (flagellum for movement)
2023 Q6(iii) Mention any two functions of the human foetal placenta.
Show Answer
Answer:
1. Exchange of nutrients, oxygen, and waste products between mother and foetus
2. Production of hormones (progesterone, estrogen, HCG) to maintain pregnancy
3. Transfer of antibodies from mother to foetus (passive immunity)
2023 Q6(iv) What is the significance of the human testes being located in scrotal sacs outside the abdomen?
Show Answer
Answer: Scrotum maintains temperature 2-3°C lower than body temperature, which is optimal for sperm production and survival.
2024 Q1(vi) A zygote which has Y chromosome inherited from the father will develop into a: (d) Boy.
Show Answer
Answer: d. Boy
2024 Q2(i)(e) Name The process of attachment of fertilized ovum to the wall of uterus.
Show Answer
Answer: Implantation
2024 Q4(i) Give the biological term for the surgical method of contraception in human females.
Show Answer
Answer: Tubectomy
2024 Q6(iv)(a) Name the process for the release of the part labelled 1 (from ovary diagram).
Show Answer
Answer: Ovulation
2024 Q6(iv)(b) Write the name of the structure marked 2 (from ovary diagram).
Show Answer
Answer: Corpus luteum
2025 Q1(iii) Assertion/Reason: Seminal vesicles pour an alkaline secretion into the semen... Reason: The female vagina is acidic...
Show Answer
Answer: Both Assertion and Reason are true and Reason is the correct explanation of Assertion.
2025 Q2(i)(a) Name The fully developed part of the ovary containing a mature ovum.
Show Answer
Answer: Graafian follicle
2025 Q2(iii)(e) Arrange the terms in correct order: Sperm duct, Seminiferous tubule, Epididymis, Efferent ducts.
Show Answer
Answer: Seminiferous tubule → Efferent ducts → Epididymis → Sperm duct
2025 Q2(iv)(a) Name the structure: The canal through which the testes descend down into the scrotum...
Show Answer
Answer: Inguinal canal
2025 Q5(iii) Differentiate between the functions of Urethra and Uterus.
Show Answer
Answer:
Urethra: Carries urine from bladder to outside; in males also carries semen
Uterus: Site of implantation and development of embryo/foetus
2025 Q7(iii) Mention any two functions of amniotic fluid.
Show Answer
Answer:
1. Acts as shock absorber, protecting foetus from mechanical injury
2. Prevents adhesion of foetus to amnion
3. Allows free movement of foetus
4. Maintains constant temperature

Chapter 6: Population, Pollution, & Ecology

Year Q No. Question
2017 Q1(a)(v) Name The international health organisation which educates people in accident prevention.
Show Answer
Answer: Red Cross Society
2017 Q1(b)(i) The prime source of chlorofluorocarbons is: D. Refrigeration equipments.
Show Answer
Answer: D. Refrigeration equipments
2017 Q1(d)(v) Rewrite the terms in correct order in a logical sequence: Caterpillar, Snake, Owl, Frog, Green leaves.
Show Answer
Answer: Green leaves → Caterpillar → Frog → Snake → Owl
2017 Q1(e)(ii) Choose the ODD one out: Formalin, Iodine, DDT, Lime. Name the CATEGORY to which the others belong.
Show Answer
Answer: DDT is odd one out
Category: Others are disinfectants/antiseptics
2017 Q1(g)(ii) Match Birth rate with Natality.
Show Answer
Answer: Birth rate → Natality
2017 Q1(g)(iv) Match Euro norms with vehicular standards.
Show Answer
Answer: Euro norms → vehicular standards
2017 Q3(b)(i) Name the kind of pollution (Water pollution diagram).
Show Answer
Answer: Water pollution
2017 Q3(b)(ii) List any three common sources of this pollution.
Show Answer
Answer:
1. Industrial waste discharge
2. Domestic sewage
3. Agricultural runoff (fertilizers, pesticides)
4. Oil spills
2017 Q3(b)(iii) Mention three harmful effects of this pollution on human health.
Show Answer
Answer:
1. Water-borne diseases (cholera, typhoid, dysentery)
2. Heavy metal poisoning (mercury, lead)
3. Skin diseases
4. Cancer (from chemical pollutants)
2017 Q3(b)(iv) Explain the term 'Pollutant'.
Show Answer
Answer: Any substance (chemical, physical, or biological) that causes pollution by being present in the environment at levels harmful to living organisms.
2017 Q3(b)(v) Name two soil pollutants.
Show Answer
Answer:
1. Pesticides (DDT)
2. Industrial waste
3. Plastic waste
4. Heavy metals
2017 Q5(b)(ii) Biological reason: Cutting of trees should be discouraged.
Show Answer
Answer: Trees:
1. Produce oxygen through photosynthesis
2. Absorb carbon dioxide, reducing greenhouse effect
3. Prevent soil erosion
4. Maintain ecological balance
5. Provide habitat for wildlife
2018 Q1(b)(ii) Which one of the following is non-biodegradable? (A. DDT).
Show Answer
Answer: A. DDT
2018 Q1(b)(v) Which one of the following is a Greenhouse gas? (B. Methane).
Show Answer
Answer: B. Methane
2018 Q1(g)(i) Name the type of pollution shown in the picture (Noise Pollution).
Show Answer
Answer: Noise pollution
2018 Q1(g)(ii) Name one source of this pollution.
Show Answer
Answer: Traffic/vehicles, industrial machinery, loudspeakers, construction activities
2018 Q1(g)(iii) How does this pollution affect human health?
Show Answer
Answer:
1. Hearing loss
2. Stress, anxiety
3. High blood pressure
4. Sleep disturbances
5. Reduced concentration
2018 Q1(g)(iv) Write one measure to reduce this pollution.
Show Answer
Answer:
1. Use of sound barriers/silencers
2. Planting trees as sound buffers
3. Enforcement of noise control laws
4. Use of ear protection
2018 Q1(g)(v) State one gaseous compound that leads to the depletion of the ozone layer and creates 'Ozone holes'.
Show Answer
Answer: Chlorofluorocarbons (CFCs)
2018 Q1(h)(i) Choose the ODD one out: Detergents, X-rays, sewage, oil spills. Name the CATEGORY to which the others belong.
Show Answer
Answer: X-rays is odd one out
Category: Others are water pollutants
2018 Q2(b)(ii) Differentiate between Demography and Population density [Definition].
Show Answer
Answer:
Demography: Statistical study of human population
Population density: Number of individuals per unit area
2018 Q4(b)(x) Technical term for The difference between the birth rate and the death rate.
Show Answer
Answer: Growth rate
2018 Q6(b)(i) Biological explanation: Education is very important for population control.
Show Answer
Answer: Education:
1. Creates awareness about family planning methods
2. Delays age of marriage
3. Empowers women to make reproductive choices
4. Increases understanding of consequences of overpopulation
2018 Q6(b)(iii) Biological explanation: All the food chains begin with green plants.
Show Answer
Answer: Green plants are producers that convert solar energy into chemical energy through photosynthesis, providing food for all other organisms in the food chain.
2019 Q1(c)(i) Biological reason: The birth rate in India is very high.
Show Answer
Answer: Reasons:
1. Early marriage
2. Illiteracy, especially among women
3. Poverty
4. Lack of awareness about family planning
5. Preference for male child
2019 Q1(c)(iv) Biological reason: Acid rain is harmful to the environment.
Show Answer
Answer: Acid rain:
1. Damages plants by leaching nutrients from soil
2. Acidifies water bodies, harming aquatic life
3. Corrodes buildings and monuments
4. Affects human respiratory system
2019 Q1(c)(v) Biological reason: All life on Earth is supported by Photosynthesis.
Show Answer
Answer: Photosynthesis:
1. Produces oxygen for respiration
2. Produces food (glucose) for all organisms
3. Maintains balance of oxygen and carbon dioxide in atmosphere
2019 Q1(f)(v) Choose the ODD one out: Polythene bag, Crop residue, Animal waste, Decaying vegetable. Name the category to which the others belong.
Show Answer
Answer: Polythene bag is odd one out
Category: Others are biodegradable wastes
2019 Q1(h)(i) Identify the type of pollution (Noise pollution picture).
Show Answer
Answer: Noise pollution
2019 Q1(h)(ii) Name one pollutant that causes the above pollution.
Show Answer
Answer: Loud sounds from vehicles, machinery, loudspeakers
2019 Q1(h)(iii) Mention the impact of this pollution on human health.
Show Answer
Answer:
1. Hearing loss
2. Stress, anxiety
3. High blood pressure
4. Sleep disturbances
5. Reduced concentration
2019 Q1(h)(iv) State one measure to control this pollution.
Show Answer
Answer:
1. Use of sound barriers/silencers
2. Planting trees as sound buffers
3. Enforcement of noise control laws
4. Use of ear protection
2019 Q1(h)(v) What is a 'Pollutant'? Explain the term.
Show Answer
Answer: Any substance (chemical, physical, or biological) that causes pollution by being present in the environment at levels harmful to living organisms.
2019 Q7(a)(v) Mention any two objectives of 'Swachh Bharat Abhiyan'.
Show Answer
Answer:
1. Elimination of open defecation
2. Proper solid waste management
3. Creating clean public spaces
4. Creating awareness about sanitation and hygiene
2020 Q1(b)(v) Explain the term Population density.
Show Answer
Answer: Number of individuals per unit area at a given time.
2020 Q2(b)(iv) Differentiate between Biodegradable waste and Non-biodegradable waste (One example).
Show Answer
Answer:
Biodegradable: Can be broken down by microorganisms (e.g., vegetable peels, paper)
Non-biodegradable: Cannot be broken down by microorganisms (e.g., plastic, glass, metals)
2020 Q4(b)(iii) Differentiate between Population control and Swachh Bharat Abhiyan (One objective).
Show Answer
Answer:
Population control: Aims to stabilize population growth through family planning
Swachh Bharat Abhiyan: Aims to create clean India through proper waste management and sanitation
2023 Q1(ii) Which one of the following is a biodegradable waste? (d) Flowers.
Show Answer
Answer: d. Flowers
2023 Q1(viii) The statistical study of human population is called: (b) Demography.
Show Answer
Answer: b. Demography
2023 Q2(i)(b) Name A genetic disorder in which the blood does not clot.
Show Answer
Answer: Haemophilia
2023 Q2(ii)(a) Arrange and rewrite the terms in each group in correct order: Snake, Rabbit, Cabbage, Hawk.
Show Answer
Answer: Cabbage → Rabbit → Snake → Hawk
2023 Q2(iv)(a) Choose the odd one out: Used bandages, Pesticides, Face masks, Syringes. Name the category to which the others belong.
Show Answer
Answer: Pesticides is odd one out
Category: Others are biomedical wastes
2023 Q2(iv)(b) Choose the odd one out: Dust, Smoke, Carbon monoxide, Effluents. Name the category to which the others belong.
Show Answer
Answer: Effluents is odd one out
Category: Others are air pollutants
2023 Q5(i) Explain the term 'Population density'.
Show Answer
Answer: Number of individuals per unit area at a given time.
2023 Q5(ii) Name the two surgical methods of population control.
Show Answer
Answer:
1. Vasectomy (for males)
2. Tubectomy (for females)
2023 Q5(iii) Mention two factors responsible for population explosion in India.
Show Answer
Answer:
1. High birth rate
2. Decreased death rate due to better medical facilities
3. Early marriage
4. Illiteracy
5. Poverty
2023 Q5(iv) Name any two resources which come under pressure due to rising population.
Show Answer
Answer:
1. Food resources
2. Water resources
3. Land/Housing
4. Energy resources
5. Educational and healthcare facilities
2023 Q5(v)(a) Name the climatic phenomenon for the increase in Earth's temperature.
Show Answer
Answer: Global warming
2023 Q5(v)(b) Mention one reason for this warming.
Show Answer
Answer: Increased greenhouse gases (CO₂, methane, CFCs) due to human activities like burning fossil fuels, deforestation, industrial processes.
2023 Q5(v)(c) What measure can be taken to prevent this climate change?
Show Answer
Answer:
1. Reduce use of fossil fuels
2. Use renewable energy sources
3. Afforestation (plant more trees)
4. Reduce deforestation
5. Use energy-efficient technologies
2024 Q1(xiv) Birth rate is the number of live births per thousand persons in: (a) 1 year.
Show Answer
Answer: a. 1 year
2024 Q2(iv)(d) Choose the odd one out: Leaves, Styrofoam, Grass, Cow Dung. Name the category to which the others belong.
Show Answer
Answer: Styrofoam is odd one out
Category: Others are biodegradable wastes
2024 Q3(iv) Give two examples of water pollutants.
Show Answer
Answer:
1. Industrial waste/chemicals
2. Domestic sewage
3. Agricultural runoff (fertilizers, pesticides)
4. Oil spills
2024 Q4(ii) State two harmful effects of acid rain on the environment.
Show Answer
Answer:
1. Damages plants by leaching nutrients from soil
2. Acidifies water bodies, harming aquatic life
3. Corrodes buildings and monuments
4. Affects human respiratory system
2024 Q4(iv) Write any two objectives of Swachh Bharat Abhiyan.
Show Answer
Answer:
1. Elimination of open defecation
2. Proper solid waste management
3. Creating clean public spaces
4. Creating awareness about sanitation and hygiene
2024 Q5(iii) "Birth rate in India is very high." Mention two reasons in support of the statement.
Show Answer
Answer:
1. Early marriage
2. Illiteracy, especially among women
3. Poverty
4. Lack of awareness about family planning
5. Preference for male child
2024 Q8(iii) Mention two harmful effects of noise pollution.
Show Answer
Answer:
1. Hearing loss
2. Stress, anxiety, high blood pressure
3. Sleep disturbances
4. Reduced concentration and productivity
2025 Q1(i) The number of live births per thousand people per year is called: (d) Natality.
Show Answer
Answer: d. Natality
2025 Q1(xii) Identify the kind of pollution caused by nuclear power plants releasing warm water back into the stream. (d) Thermal pollution.
Show Answer
Answer: d. Thermal pollution
2025 Q3(iv) State any two disadvantages of living close to an airport.
Show Answer
Answer:
1. Noise pollution affecting health and sleep
2. Air pollution from aircraft emissions
3. Risk of accidents
4. Reduced property values
2025 Q4(iv) State any two harmful effects of acid rain.
Show Answer
Answer:
1. Damages plants by leaching nutrients from soil
2. Acidifies water bodies, harming aquatic life
3. Corrodes buildings and monuments
4. Affects human respiratory system
2025 Q5(ii) What are biomedical wastes? Give an example.
Show Answer
Answer:
Definition: Waste generated during diagnosis, treatment, or immunization of humans or animals, or in research activities
Example: Used syringes, bandages, surgical waste, contaminated materials
2025 Q7(ii)(a) Mention any one reason for reduction in the death rate.
Show Answer
Answer:
1. Better medical facilities and healthcare
2. Improved sanitation and hygiene
3. Vaccination programs
4. Better nutrition
2025 Q7(ii)(b) Name any one resource that is under pressure due to population explosion.
Show Answer
Answer:
1. Food resources
2. Water resources
3. Land/Housing
4. Energy resources
5. Educational and healthcare facilities
2025 Q7(iv)(a) Expand the abbreviation: CFC.
Show Answer
Answer: Chlorofluorocarbon
2025 Q7(iv)(b) Expand the abbreviation: CNG.
Show Answer
Answer: Compressed Natural Gas
2025 Q8(iii) Mention any two objectives of Swachh Bharat Abhiyan.
Show Answer
Answer:
1. Elimination of open defecation
2. Proper solid waste management
3. Creating clean public spaces
4. Creating awareness about sanitation and hygiene