CBSE Class 12 Biology Reproduction in Flowering Plants Question Bank

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BIOLOGY

CHAPTER: 1 REPRODUCTION IN ORGANISMS
(QUESTION BANK)

1. No organism is immortal, then why do we say there is no natural death in single - celled organisms? [1 Mark]

Answer:
1. In single-celled organisms like amoeba, the parent cell divides into two by mitosis to form new individual organisms.
2. Therefore, there is no natural death in single-celled organisms.

Teacher's Note:
a) Single-celled organisms multiply through cell division.
b) The parent body is distributed among the offspring, avoiding old age and death.

2. What is the significance of reproduction? [1 Mark]

Answer:
1. Reproduction ensures the continuity of species generation after generation.
2. It introduces variations essential for evolution and adaptation.

Teacher's Note:
a) It is a biological process enabling organisms to create new organisms similar to themselves.
b) Without it, species would become extinct over time.

3. Name the type of reproduction wherein the off springs produced are identical to each other and to the parent. [1 Mark]

Answer:
1. Asexual reproduction.

Teacher's Note:
a) Offspring produced asexually are genetically identical copies called clones.
b) It involves a single parent without the fusion of gametes.

4. Name the stage of growth and maturity in the life of animals before they can reproduce sexually. [1 Mark]

Answer:
1. Juvenile phase (or vegetative phase in plants).

Teacher's Note:
a) This phase marks the period of growth required before an organism attains sexual maturity.
b) Its duration varies across different species.

5. Name the scientific name of the plant which flower once in 12 years. [1 Mark]

Answer:
1. Strobilanthus kunthiana (Neelakuranji).

Teacher's Note:
a) It flowered profusely in September-October 2006, turning hilly tracts blue in Kerala, Karnataka and Tamil Nadu.
b) Binomial nomenclature rules require underlining or italicizing scientific names.

6. Name the type of fertilization wherein the survival of the organism up to adulthood is threatened. [1 Mark]

Answer:
1. External fertilization.

Teacher's Note:
a) Gametes released in the external medium are vulnerable to predators.
b) This drastically reduces the survival rate of offspring to adulthood.

7. Name the structure from where every sexually reproducing organism begins their life. [1 Mark]

Answer:
1. Zygote (single-celled).

Teacher's Note:
a) The fusion of male and female gametes results in a diploid zygote.
b) It serves as the vital link between two generations.

8. What is a meiocyte? [1 Mark]

Answer:
1. A diploid cell that undergoes meiosis to produce haploid gametes.

Teacher's Note:
a) Meiocytes contain twice the number of chromosomes (2n) compared to gametes (n).
b) Also known as gamete mother cells.

9. What do you mean by clones? [1 Mark]

Answer:
1. Morphologically and genetically similar individuals.

Teacher's Note:
a) Clones are produced through asexual reproduction.
b) They share identical DNA sequences derived from a single parent.

10. What is a vegetative phase in plants? [1 Mark]

Answer:
1. The period of vegetative growth and maturity in plants before they begin to flower.

Teacher's Note:
a) It is synonymous with the juvenile phase in animals.
b) Plants build structural biomass during this phase.

11. Name the type of plants that show clear cut vegetative, reproductive and senescent phases. [1 Mark]

Answer:
1. Annual and biennial plants.

Teacher's Note:
a) These plants show clear-cut distinct phases in their life cycles.
b) Perennial plants often show obscure or overlapping phases.

12. Name the plant which flower only once in their life time. [1 Mark]

Answer:
1. Bamboo species (and Strobilanthus kunthiana).

Teacher's Note:
a) Most bamboos flower only once in 50-100 years, produce large numbers of fruits and die.
b) Monocarpic plants flower once and then die.

13. In seed plants how the non-motile gametes are carried to female gamete? [1 Mark]

Answer:
1. By pollen tubes.

Teacher's Note:
a) Male gametes are non-motile in seed plants (gymnosperms and angiosperms).
b) Pollen tubes deliver them directly to the female gamete inside the ovule.

14. Differentiate between asexual and sexual method of reproduction. [2 Marks]

Answer:

Teacher's Note:
a) Asexual reproduction is rapid but lacks diversity.
b) Sexual reproduction promotes evolution through recombination.

15. Gametes are always haploid .How are the gametes produced from a haploid plant body and a diploid plant body? [2 Marks]

Answer:
1. A haploid plant body produces gametes by mitotic division.
2. A diploid plant body produces gametes by meiotic division of specialized diploid cells called meiocytes.

Teacher's Note:
a) Organisms with haploid plant bodies (like algae and bryophytes) undergo mitosis for gametogenesis.
b) Diploid organisms (like pteridophytes, gymnosperms, angiosperms) use meiosis.

16. How do the following organisms reproduce? Yeast, Amoeba. [2 Marks]

Answer:
1. Yeast reproduces asexually by budding.
2. Amoeba reproduces asexually by binary fission.

Teacher's Note:
a) Budding involves small outgrowths detaching from the parent.
b) Binary fission involves equal division of the parent cell into two daughter cells.

17. Life spans of organisms are not necessarily correlated with their sizes. Explain [2 Marks]

Answer:
1. Size and life span do not have a direct proportional relationship in all organisms.
2. For example, the sizes of a crow and a parrot are roughly similar, yet their life spans are vastly different (15 years and 140 years respectively).

Teacher's Note:
a) Similarly, a mango tree has a much shorter life span compared to a peepal tree despite similar tree sizes.
b) Life span is genetically regulated.

18. Name the asexual reproductive structures of the following: Chlamydomonas, Penicillum, Hydra, Sponge. [2 Marks]

Answer:
1. Chlamydomonas - Zoospores.
2. Penicillium - Conidia.
3. Hydra - Buds.
4. Sponge - Gemmules.

Teacher's Note:
a) Zoospores are microscopic motile structures.
b) Conidia are non-motile spores produced exogenously.

19. Explain the following terms. Isogametes, Anisogametes, staminate flower, Pistillate flower. [2 Marks]

Answer:
1. Isogametes: Gametes that are morphologically similar and indistinguishable.
2. Anisogametes: Gametes that are morphologically distinct and dissimilar in size.
3. Staminate flower: A unisexual male flower bearing stamens.
4. Pistillate flower: A unisexual female flower bearing pistils.

Teacher's Note:
a) Isogamy occurs in some algae.
b) Unisexual flowers lack either stamens or pistils.

20. Why are Chara and Marchantia are referred to as monoecious and dioecious plants ? [2 Marks]

Answer:
1. Chara is monoecious because male and female sex organs (antheridiophore and oogoniophore) are present on the same plant body.
2. Marchantia is dioecious because male and female sex organs are present on separate plant bodies.

Teacher's Note:
a) Monoecious means bisexual condition on one plant.
b) Dioecious means unisexual condition on separate plants.

21. What are hermaphrodite? Give an example. [1 Mark]

Answer:
1. Animals that possess both male and female reproductive organs in the same individual are called hermaphrodites. Example: Earthworm.

Teacher's Note:
a) Also referred to as bisexual animals.
b) Other examples include leeches and tapeworms.

22. Why do you refer Water Hyacinth as an invasive weed? Why is it difficult to get rid off them? [2 Marks]

Answer:
1. Water hyacinth (Eichhornia crassipes) is called an invasive weed because it grows abundantly in stagnant water, drains oxygen, and suffocates aquatic life.
2. It is difficult to get rid of because it propagates vegetatively at a phenomenal rate and spreads across water bodies rapidly.

Teacher's Note:
a) It was introduced in India due to its beautiful flowers and shape of leaves.
b) It is known as the 'Terror of Bengal'.

23. Why the number of male gametes produced is more than the number of female gamete? [1 Mark]

Answer:
1. A large number of male gametes are produced to compensate for the massive loss suffered during transfer.

Teacher's Note:
a) Female gametes are sessile and protected, whereas male gametes need to travel.
b) This ensures successful fertilization.

24. Name the gametes produced by staminate and pistillate flowers. [1 Mark]

Answer:
1. Staminate flowers produce pollen grains (male gametes), and pistillate flowers produce egg cells (female gametes).

Teacher's Note:
a) Staminate flowers are male flowers.
b) Pistillate flowers are female flowers.

25. Why are offsprings of oviparous animals at a greater risk as compared to offsprings of viviparous animals? [2 Marks]

Answer:
1. In oviparous animals, fertilized eggs are laid outside, exposing them to harsh environmental conditions and predators.
2. In viviparous animals, the development of the embryo takes place inside the female body, ensuring better protection and care.

Teacher's Note:
a) Oviparous means egg-laying animals like reptiles and birds.
b) Viviparous means giving birth to live young ones like most mammals.

26. Cell division is itself a mode of reproduction .Name two single celled organisms and explains this. [2 Marks]

Answer:
1. Two single-celled organisms: Amoeba and Paramecium.
2. Explanation: In these organisms, cell division (mitotic division) results in an increase in the number of individuals, as the parent cell divides into two new daughter cells, making cell division synonymous with reproduction.

Teacher's Note:
a) Unicellular organisms reproduce primarily via cell division.
b) This process does not involve gamete fusion.

27. What are zoospores ? Why are they referred so? [1 Mark]

Answer:
1. Zoospores are microscopic, motile asexual spores.
2. They are called zoospores because they possess flagella and can swim.

Teacher's Note:
a) Common in algae like Chlamydomonas.
b) Facilitates active dispersal in water.

28. What do the following parts of a flower develop into after fertilization? Ovary, zygote, ovary wall, ovules. [2 Marks]

Answer:
1. Ovary develops into Fruit.
2. Zygote develops into Embryo.
3. Ovary wall develops into Pericarp (fruit wall).
4. Ovules develop into Seeds.

Teacher's Note:
a) Post-fertilization changes lead to seed and fruit formation in angiosperms.
b) Sepals, petals and stamens usually wither and fall off.

29. Mention the three phases in the life cycle of plants and animals. [1 Mark]

Answer:
1. Juvenile phase (vegetative phase), Reproductive phase, and Senescent phase.

Teacher's Note:
a) Juvenile phase is pre-reproductive.
b) Senescence represents old age leading to death.

30. Study the figure, label the parts [2 Marks]

[Figure: Diagram of a fruit in section with two labelled parts: A (inner part) and B (outer wall)]

Answer:
1. A - Seed, B - Pericarp.

Teacher's Note:
a) The ovule develops into the seed after fertilization.
b) The ovary wall develops into the pericarp (fruit wall).

31. What are vegetative propagules? Name the vegetative propagules of the following plants .Ginger, Agave, Bryophyllum ,Water hyacinth. [2 Marks]

Answer:
1. Vegetative propagules are units of vegetative plant parts capable of giving rise to new offspring.
2. Ginger: Rhizome, Agave: Bulbils, Bryophyllum: Adventitious buds on leaves, Water hyacinth: Offsets.

Teacher's Note:
a) Vegetative propagation is a type of asexual reproduction.
b) Ensures exact copies of the parent plant are produced rapidly.

32. What are continuous breeders and seasonal breeders? [2 Marks]

Answer:
1. Continuous breeders: Animals that are reproductively active throughout their reproductive phase (e.g., mice, humans, rabbits).
2. Seasonal breeders: Animals that reproduce only during specific favorable seasons in their reproductive cycle (e.g., dogs, birds, frogs).

Teacher's Note:
a) Placental mammals exhibit these reproductive cycles.
b) Seasonal breeders are typically wild animals.

33. Where does syngamy occur?Explain with examples . [2 Marks]

Answer:
1. Syngamy (fusion of gametes) can occur either externally (outside the body) or internally (inside the body).
2. External fertilization: Occurs in water for organisms like bony fishes and amphibians (e.g., frogs). Internal fertilization: Occurs inside the female body for terrestrial organisms like birds and mammals (e.g., humans).

Teacher's Note:
a) Syngamy results in diploid zygote formation.
b) Medium is crucial for gamete transfer.

34. Explain the features exhibited by the organisms showing external fertilization to enhance the chances of syngamy .What is the disadvantage of external fertilization ? [3 Marks]

Answer:
1. Organisms show great synchrony between the sexes and release a large number of gametes into the surrounding medium (water) to enhance chances of syngamy.
2. Example: Bony fishes and frogs release millions of gametes.
3. Disadvantage: Offspring are extremely vulnerable to predators throughout their early life, threatening their survival up to adulthood.

Teacher's Note:
a) External fertilization requires an external medium like water.
b) High mortality rate is a major drawback.

35. Differentiate between oestrus and menstrual cycle with examples. [2 Marks]

Answer:
1. Oestrus cycle occurs in non-primate mammals (like cows, sheep, dogs) and involves behavioral changes during heat.
2. Menstrual cycle occurs in primate mammals (like monkeys, apes, humans) and involves cyclical bleeding (menstruation) at the end of the cycle.

Teacher's Note:
a) Both are cyclic changes during the reproductive phase of females.
b) The endometrium is reabsorbed in oestrus and shed in menstrual cycles.

36. Write the sexuality in the following organisms.(a) earthworm (b) Cockroach (c) Chara (d) Marchantia (e) Sweet Potato (f)Leech. [3 Marks]

Answer:
1. (a) Earthworm - Bisexual (Hermaphrodite).
2. (b) Cockroach - Unisexual (Dioecious).
3. (c) Chara - Monoecious (Bisexual).
4. (d) Marchantia - Dioecious (Unisexual).
5. (e) Sweet Potato - Bisexual.
6. (f) Leech - Bisexual (Hermaphrodite).

Teacher's Note:
a) Bisexual/monoecious means both male and female organs in one individual.
b) Unisexual/dioecious means separate male and female individuals.

37. What is parthenogenesis? Give an example. [1 Mark]

Answer:
1. Parthenogenesis is the development of an organism directly from an unfertilized female gamete (egg). Example: Honeybees, rotifers, and some lizards.

Teacher's Note:
a) Occurs without fertilization.
b) Common in certain insects and reptiles.

38. What are oviparous and viviparous animals? Give examples. [2 Marks]

Answer:
1. Oviparous animals lay fertilized or unfertilized eggs covered in hard calcareous shells outside (e.g., birds, reptiles).
2. Viviparous animals give birth to young ones as development of the zygote takes place inside the female body (e.g., humans, cows).

Teacher's Note:
a) Oviparous embryos develop outside the parent.
b) Viviparous embryos receive nutrition through the placenta from the mother.

39. Give the term for the following figure A,B and C . [3 Marks]

[Figure: Three stages labeled A, B, and C of sexual reproduction; A shows fusion of gametes, B shows the zygote, C shows the new individual]

Answer:
1. Figure A: Fusion of gametes (syngamy).
2. Figure B: Zygote.
3. Figure C: New individual.

Teacher's Note:
a) Fusion of gametes forms the diploid zygote.
b) The zygote develops into a new individual.
c) Fusion of gametes is called syngamy.

40. Give the term for kinds of gametes in the given figures A and B . In the figure A give the specific terms for the gametes [3 Marks]

[Figure: Figure A shows heterogametes with a large non-motile egg and a small motile antherozoid/sperm; Figure B shows isogametes which are morphologically similar flagellated cells]

Answer:
1. Figure A represents heterogametes, and Figure B represents isogametes.
2. The specific terms for gametes in Figure A are egg (or female gamete) and antherozoid (or male gamete / sperm).

Teacher's Note:
a) Isogametes are morphologically similar and cannot be categorized as male and female.
b) Heterogametes are distinctly separated into male and female types.
c) Always specify both the general category and the specific gamete names when asked.

41. Child marriages are more prevalent in our society. i) As a student of biology how will you support a ban stating the biological reasons for the same and give valid reasons .
ii) Will you stand up against this social issue if you are a witness of a child marriage. [4 Marks]

Answer:
1. Biologically, early marriage leads to early pregnancy when the female reproductive system is not fully mature, causing high maternal and infant mortality rates.
2. It impairs the physical and mental growth of the young mother and child, leading to malnutrition and developmental disorders.
3. Yes, as a responsible citizen and biology student, I will strongly oppose and report child marriage to protect human health and rights.

Teacher's Note:
a) This question integrates biological concepts with societal awareness and ethics.
b) Ensure all parts (biological reasons and personal stand) are clearly addressed to secure full marks.
c) Legal age of marriage in India is set to prevent these exact physiological complications.

CHAPTER 1 : REPRODUCTION IN ORGANISMS

Q.No. 1. Parent cell divides to give rise to new individuals [1 Mark]

Answer:
1. Definition or core concept of cell division in reproduction.
2. Forms the basis of asexual reproduction.

Teacher's Note:
a) Simple one-word or one-line answers are expected for such marking scheme points.
b) Refers to unicellular organisms primarily.

Q.No. 2. Continuity of species [1 Mark]

Answer:
1. Reproduction ensures generation-after-generation survival of a species.
2. Prevents extinction of life forms on Earth.

Teacher's Note:
a) Emphasizes the fundamental biological significance of reproduction.

Q.No. 3. Asexual reproduction [1 Mark]

Answer:
1. Offspring produced by a single parent with or without involvement of gamete formation.
2. Results in clones.

Teacher's Note:
a) Clones are morphologically and genetically identical individuals.

Q.No. 4. Juvenile phase [1 Mark]

Answer:
1. The phase of growth before an organism reaches reproductive maturity.
2. Also known as the vegetative phase in plants.

Teacher's Note:
a) Duration varies greatly across different organisms.

Q.No. 5. Strobilanthus kunthiana [1 Mark]

Answer:
1. Plant species that flowers once in 12 years.
2. Famous for mass flowering in the hilly areas of Kerala, Karnataka, and Tamil Nadu.

Teacher's Note:
a) Classic example of a perennial plant showing unusual flowering phenomenon.

Q.No. 6. External fertilisation [1 Mark]

Answer:
1. Syngamy occurs outside the body of organisms in an external medium (usually water).
2. Seen in bony fishes and amphibians.

Teacher's Note:
a) Organisms show great synchrony between sexes in external fertilization.

Q.No. 7. Zygote [1 Mark]

Answer:
1. The vital diploid single cell formed by the fusion of male and female gametes.
2. Acts as the vital link between organisms of one generation and the next.

Teacher's Note:
a) Every sexually reproducing organism starts life as a single-celled zygote.

Q.No. 8. Gamete mother cell undergo meiosis [1 Mark]

Answer:
1. Specialized diploid cells (meiocytes) undergo reduction division.
2. Produces haploid gametes.

Teacher's Note:
a) Ensures restoration of chromosome number in the next generation.

Q.No. 9. Morphologically and genetically similar individuals [1 Mark]

Answer:
1. Definition of clones produced during asexual reproduction.
2. Individuals share identical genetic makeup.

Teacher's Note:
a) Half mark is awarded for morphological similarity and half for genetic similarity.

Q.No. 10. Period of growth in plants [1 Mark]

Answer:
1. Vegetative phase or juvenile phase.
2. Period required before entering the reproductive phase.

Teacher's Note:
a) Pre-reproductive phase in the life cycle of living organisms.

Q.No. 11. Annual , biennial [1 Mark]

Answer:
1. Categories of flowering plants based on the duration of their life cycle.
2. Annuals complete life cycle in one season; biennials take two seasons.

Teacher's Note:
a) Half mark allotted for each correct term.

Q.No. 12. Bamboo [1 Mark]

Answer:
1. Monocarpic plant species that flowers only once in their lifetime, generally after 50 - 100 years.
2. Produces large number of fruits and dies.

Teacher's Note:
a) Excellent example of unusual flowering behavior in perennial plants.

Q.No. 13. Pollen grains [1 Mark]

Answer:
1. Pollen grains carry the non-motile male gametes to the female gamete in seed plants.
2. Pollen grains are transferred to the stigma by pollination and release male gametes through the pollen tube.

Teacher's Note:
a) Pollen grains represent the male gametophytes.
b) Microsporogenesis produces pollen grains inside the anther lobes.

Q.No. 14. Single parent, two parents with or without gamete formation, fusion of gametes [½ x 4]

Answer:
1. Asexual reproduction involves a single parent, whereas sexual reproduction involves two parents.
2. Asexual reproduction may occur with or without gamete formation, whereas sexual reproduction involves the fusion of gametes.

Teacher's Note:
a) Asexual reproduction produces genetically identical clones.
b) Sexual reproduction introduces genetic variation through recombination during gametogenesis and fertilization.

Q.No. 15. Mitosis by haploid, meiosis by diploid [1 x 2]

Answer:
1. Haploid parent bodies undergo mitosis to produce gametes.
2. Diploid parent bodies undergo meiosis to produce gametes.

Teacher's Note:
a) Mitosis is an equational division maintaining chromosome number.
b) Meiosis is a reduction division reducing chromosome number from diploid to haploid.

Q.No. 16. Budding, binary fission [1 x 2]

Answer:
1. Budding: Yeast.
2. Binary fission: Amoeba.

Teacher's Note:
a) Both are common modes of asexual reproduction in unicellular organisms.
b) Binary fission divides the parent cell into two equal halves.

Q.No. 17. Size of crow and parrot are not very different, life span is 15 and 140 years [1 x 2]

Answer:
1. The life span of a crow is about 15 years.
2. The life span of a parrot is about 140 years.

Teacher's Note:
a) Life span is not necessarily correlated with the size of an organism.
b) Evolutionary adaptations and genetic programming determine organismal longevity.

Q.No. 18. Zoospores, Conidia, Buds, Gemmules [½ x 4]

Answer:
1. Chlamydomonas: Zoospores.
2. Penicillium: Conidia.
3. Hydra: Buds.
4. Sponges: Gemmules.

Teacher's Note:
a) Zoospores are microscopic motile structures.
b) Gemmules are internal asexual buds specialized for surviving unfavorable conditions.

Q.No. 19. Similar in appearance, dissimilar in appearance, male flower, female flower [½ x 4]

Answer:
1. Homogametes are similar in appearance, whereas heterogametes are morphologically distinct (male and female).
2. Staminate flowers are male flowers containing stamens, whereas pistillate flowers are female flowers containing pistils.

Teacher's Note:
a) Algae often produce homogametes (isogametes).
b) Higher plants and animals typically produce heterogametes.

Q.No. 20. Both sex organs in the same individual, separate individuals [1 x 2]

Answer:
1. Bisexual organisms have both male and female sex organs in the same individual.
2. Unisexual organisms have male and female sex organs in separate individuals.

Teacher's Note:
a) Bisexual plants are also called monoecious.
b) Unisexual plants and animals are referred to as dioecious.

Q.No. 21. Bisexual animals, earthworm or any other [1 + 1]

Answer:
1. Bisexual animal: Earthworm.
2. Unisexual animal: Cockroach.

Teacher's Note:
a) Bisexual animals are also known as hermaphrodites.
b) Unisexual species exhibit distinct male and female individuals.

Q.No. 22. Drains oxygen from water, death of fishes [1 x 2]

Answer:
1. Water hyacinth grows rapidly and drains dissolved oxygen from the water.
2. Oxygen depletion leads to the suffocation and death of fishes.

Teacher's Note:
a) It is known as the Terror of Bengal.
b) It propagates vegetatively at an alarming rate.

Q.No. 23. Fail to reach female gamete, to compensate loss during transport [1 x 2]

Answer:
1. A large number of male gametes fail to reach the female gamete during transport.
2. Producing excess male gametes compensates for this massive loss during transit.

Teacher's Note:
a) Female gametes are generally stationary and produced in smaller numbers.
b) External fertilization increases the necessity for higher gamete production.

Q.No. 24. Male gamete, female gamete [1 x 2]

Answer:
1. Syngamy is the complete and permanent fusion of male and female gametes.
2. The two types of gametes involved are male gametes and female gametes.

Teacher's Note:
a) Syngamy results in the formation of a diploid zygote.
b) In some organisms, fertilization can occur without syngamy (parthenogenesis).

Q.No. 25. Viviparous animals - proper care and protection, chances of survival is more in oviparous [1 x 2]

Answer:
1. Viviparous animals provide proper embryonic care and protection inside the mother's body.
2. In oviparous animals, eggs laid in the environment are vulnerable to predators and harsh conditions.

Teacher's Note:
a) Zygote development occurs inside the female reproductive tract in viviparity.
b) Oviparous animals lay fertilized or unfertilized eggs covered by hard calcareous shells.

Q.No. 26. Binary fission in Amoeba cell divides into two halves, buds in yeast attached to parent gets separated and mature into yeast [½ x 4]

Answer:
1. In Amoeba, the parent cell divides into two equal halves during binary fission.
2. In yeast, small buds form, stay attached temporarily to the parent, get separated, and mature into new yeast cells.

Teacher's Note:
a) Binary fission is a form of cell division resulting in two daughter cells.
b) Budding involves unequal division where a small outgrowth develops into a new organism.

Q.No. 27. Asexual reproductive structures of Fungi, algae, microscopic motile structures [1 x 2]

Answer:
1. Zoospores are the microscopic motile structures found in many algae.
2. They possess flagella for active movement.

Teacher's Note:
a) Zoospores enable rapid dispersal in aquatic environments.
b) Fungi primarily produce non-motile spores like conidia or sporangiospores.

Q.No. 28. Fruit, embryo, pericarp, seed [½ x 4]

Answer:
1. The ovary develops into a fruit.
2. The ovule develops into a seed, and the ovary wall develops into the pericarp.

Teacher's Note:
a) Fertilization transforms floral organs significantly.
b) Sepals, petals, and stamens usually wither and fall off.

Q.No. 29. Vegetative, reproductive, senescent phases [½ x 2 + 1]

Answer:
1. Juvenile phase (vegetative phase in plants).
2. Reproductive phase.
3. Senescent phase.

Teacher's Note:
a) The juvenile phase represents the period of growth before reproductive maturity.
b) Senescence marks the end of the reproductive phase leading to death.

Q.No. 30. A - Seed, B - Pericarp [1 x 2]

Answer:
1. A - Seed.
2. B - Pericarp.

Teacher's Note:
a) The ovule matures into the seed.
b) The ovary wall forms the protective fruit wall known as the pericarp.

Q.No. 31. Structures used for vegetative propagation, Rhizome, bulbil, leaf buds, offset [1 x ½ x 4]

Answer:
1. Rhizome (e.g., Ginger).
2. Bulbil (e.g., Agave).
3. Leaf buds (e.g., Bryophyllum).
4. Offset (e.g., Eichhornia).

Teacher's Note:
a) Vegetative propagation is a type of asexual reproduction.
b) It produces genetically identical offspring from vegetative parts of the parent plant.

Q.No. 32. Reproductively active throughout their reproductive phase, exhibit only during favourable seasons [½ x 2]

Answer:
1. Seasonal breeders exhibit reproductive activity only during favorable seasons in their reproductive phase.
2. Continuous breeders are reproductively active throughout their entire reproductive phase.

Teacher's Note:
a) Most wild mammals are seasonal breeders.
b) Humans and some farm animals are continuous breeders.

Q.No. 33. External fertilization - outside, amphibians; internal fertilization - internal, reptiles [½ x 2]

Answer:
1. External fertilization: Amphibians (e.g., Frogs).
2. Internal fertilization: Reptiles (e.g., Snakes) and Mammals.

Teacher's Note:
a) External fertilization takes place outside the female body in a medium like water.
b) Internal fertilization occurs inside the female body.

Q.No. 34. Synchrony between sexes, release of large number of gametes, vulnerable to predators [1 x 3]

Answer:
1. There must be great synchrony between the sexes to release gametes simultaneously.
2. A very large number of gametes must be released into the surrounding medium.
3. Offspring are extremely vulnerable to predators, threatening their survival.

Teacher's Note:
a) Bony fishes and amphibians are classic examples.
b) External fertilization requires an external aquatic medium.

Q.No. 35. Female placental animals, exhibit cyclical changes, non-primate, cows, primate, monkeys [6 x ½]

Answer:
1. Non-primate mammals (e.g., cows, sheep) exhibit an oestrus cycle.
2. Primate mammals (e.g., monkeys, apes, humans) exhibit a menstrual cycle.
3. Both cycles occur in female placental mammals during their reproductive phase.

Teacher's Note:
a) Oestrus cycle is marked by behavioral changes during heat.
b) Menstrual cycle involves shedding of the endometrium with bleeding.

Q.No. 36. Bisexual - leech, earthworm, chara, sweet potato; unisexual - cockroach, Marchantia [6 x ½]

Answer:
1. Bisexual organisms: Leech, Earthworm, Chara, Sweet potato.
2. Unisexual organisms: Cockroach, Marchantia.
3. Bisexual species possess both male and female reproductive structures in the same individual.

Teacher's Note:
a) Chara is a monoecious alga.
b) Marchantia is a dioecious bryophyte.

Q.No. 37. Female gamete, undergoes development, to form new organism, without fertilization, Rotifers [½ x 4 x 1]

Answer:
1. Parthenogenesis is the development of a new organism from the female gamete without fertilization.
2. Example: Rotifers, honeybees, and some lizards.

Teacher's Note:
a) It is a form of asexual reproduction resembling sexual reproduction due to gamete involvement.
b) Fertilization is bypassed entirely.

Q.No. 38. Oviparous - fertilised eggs covered by hard calcareous shell, incubation, young ones hatch out, e.g. reptiles; Viviparous - zygote develops into a young one inside the body of female, e.g. mammals [1 x ½ x 2]

Answer:
1. Oviparous animals lay fertilized eggs covered by hard calcareous shells, and young ones hatch out later (e.g., reptiles and birds).
2. Viviparous animals develop the zygote into a young one inside the female body, giving birth to live young (e.g., mammals).

Teacher's Note:
a) Oviparous embryos develop outside the mother's body.
b) Viviparous species ensure higher embryonic protection and nutrition.

Q.No. 39. (A) Fusion of gametes (B) zygote (C) new individual [1 x 3]

Answer:
1. Fusion of gametes forms the zygote (A).
2. The zygote develops into the embryo (B).
3. The embryo eventually develops into a new individual (C).

Teacher's Note:
a) Post-fertilization events are crucial for embryogenesis.
b) Cell division and cell differentiation are key processes in this phase.

Q.No. 40. (A) Heterogametes (B) Homogametes, Egg and Sperm [1 x 3]

Answer:
1. Heterogametes are morphologically distinct types of gametes.
2. The male heterogamete is termed the sperm or antherozoid.
3. The female heterogamete is termed the egg or ovum.

Teacher's Note:
a) In contrast, homogametes cannot be categorized into male and female types.
b) Heterogamy is widespread in higher plants and animals.

Q.No. 41. (i) Genuine and valid reason (ii) Yes, example of a real event [2 x 2]

Answer:
1. Genuine and valid reason: child marriage leads to early pregnancy when the body and reproductive system are not mature, risking the health of mother and child.
2. It also impairs physical and mental development, so a ban is biologically justified.
3. Yes, I would stand up against child marriage and report it, citing a real event as an example.
4. Awareness and legal action protect health and rights.

Teacher's Note:
a) Combines biological reasoning with social responsibility.
b) Both parts, the biological reason and the personal stand, must be answered.