MCQs on Reproduction in Organisms – Class 12 Biology
MCQs on Reproduction in Organisms – Class 12 Biology
CBSE Class 12 Biology | Unit I: Reproduction
NCERT-Based MCQs with Answers and Concept-Clearing Explanations
Section A: Introduction to Reproduction
Q1. Reproduction is best defined as the process by which organisms
A. increase their body size
B. produce new individuals of the same species
C. adapt to the environment
D. obtain energy
Correct Answer: B
Explanation: Reproduction is the biological process that ensures continuity of a species by producing offspring similar to the parents. It does not directly help in survival of an individual but is essential for species survival.
Q2. Which of the following is NOT a characteristic of reproduction?
A. Ensures continuity of species
B. Maintains population
C. Essential for individual survival
D. Transfers genetic information
Correct Answer: C
Explanation: An individual organism can survive without reproducing, but reproduction is vital for the survival of the species as a whole.
Q3. Variation introduced during reproduction is important because it
A. increases body size
B. causes diseases
C. helps in evolution
D. stops mutation
Correct Answer: C
Explanation: Variations provide raw material for natural selection, allowing species to adapt and evolve in changing environments.
Section B: Asexual Reproduction
Q4. Asexual reproduction is characterized by
A. fusion of gametes
B. involvement of two parents
C. formation of genetically identical offspring
D. high genetic variation
Correct Answer: C
Explanation: Asexual reproduction involves a single parent and produces offspring genetically identical to the parent, known as clones.
Q5. Which of the following organisms reproduces by binary fission?
A. Hydra
B. Yeast
C. Amoeba
D. Spirogyra
Correct Answer: C
Explanation: Amoeba reproduces by binary fission, where the parent cell divides into two equal daughter cells.
Q6. Multiple fission is commonly observed in
A. Paramecium
B. Amoeba during unfavorable conditions
C. Hydra
D. Planaria
Correct Answer: B
Explanation: Under unfavorable conditions, Amoeba undergoes multiple fission, producing many daughter cells at once.
Q7. Budding is a mode of asexual reproduction seen in
A. Amoeba
B. Hydra
C. Plasmodium
D. Spirogyra
Correct Answer: B
Explanation: In Hydra, a small outgrowth (bud) develops from the parent body and later detaches to form a new individual.
Q8. Fragmentation as a reproductive method occurs in
A. Hydra
B. Amoeba
C. Spirogyra
D. Yeast
Correct Answer: C
Explanation: In Spirogyra, the filament breaks into fragments, and each fragment grows into a new organism.
Q9. Which asexual reproductive structure helps fungi survive adverse conditions?
A. Zygote
B. Spore
C. Gamete
D. Bud
Correct Answer: B
Explanation: Spores are thick-walled structures resistant to harsh conditions and germinate when conditions become favorable.
Q10. Vegetative propagation is a type of asexual reproduction commonly seen in
A. animals
B. fungi
C. flowering plants
D. bacteria
Correct Answer: C
Explanation: Vegetative propagation occurs in flowering plants using roots, stems, or leaves (e.g., potato, Bryophyllum).
Section C: Sexual Reproduction – General Features
Q11. Sexual reproduction involves
A. one parent only
B. no gamete formation
C. fusion of male and female gametes
D. only mitotic divisions
Correct Answer: C
Explanation: Sexual reproduction involves formation and fusion of male and female gametes, resulting in genetic variation.
Q12. The fusion of gametes is known as
A. fertilisation
B. pollination
C. germination
D. propagation
Correct Answer: A
Explanation: Fertilisation is the process where male and female gametes fuse to form a zygote.
Q13. Sexual reproduction leads to greater genetic variation because of
A. mitosis
B. meiosis
C. cloning
D. fragmentation
Correct Answer: B
Explanation: Meiosis introduces genetic recombination and independent assortment, increasing variation.
Q14. Which phase is common to all sexually reproducing organisms?
A. Pollination
B. Gametogenesis
C. Seed formation
D. Budding
Correct Answer: B
Explanation: Gametogenesis (formation of gametes) is a universal phase in sexual reproduction.
Section D: Sexual Reproductive Cycles
Q15. The haplontic life cycle is commonly seen in
A. humans
B. algae like Chlamydomonas
C. mosses
D. ferns
Correct Answer: B
Explanation: In haplontic life cycles, the organism is haploid and the zygote is the only diploid stage.
Q16. In diplontic life cycles, the dominant phase is
A. haploid
B. diploid
C. triploid
D. polyploid
Correct Answer: B
Explanation: In diplontic organisms (e.g., humans), the diploid stage dominates the life cycle.
Q17. Haplo-diplontic life cycle is characteristic of
A. fungi only
B. animals
C. some algae and bryophytes
D. bacteria
Correct Answer: C
Explanation: Haplo-diplontic life cycle has both haploid and diploid multicellular stages.
Q18. Alternation of generations refers to
A. asexual and sexual phases alternating
B. alternation of parents
C. alternation of habitats
D. alternation of chromosomes
Correct Answer: A
Explanation: Alternation of generations involves regular alternation between haploid (gametophyte) and diploid (sporophyte) phases.
Section E: Events in Sexual Reproduction
Q19. Formation of gametes occurs during
A. sporogenesis
B. gametogenesis
C. embryogenesis
D. fertilisation
Correct Answer: B
Explanation: Gametogenesis is the process of formation of male and female gametes.
Q20. Zygote formation takes place during
A. meiosis
B. pollination
C. fertilisation
D. embryogenesis
Correct Answer: C
Explanation: Fertilisation results in the formation of a diploid zygote.
Q21. Embryogenesis refers to
A. formation of gametes
B. development of embryo from zygote
C. formation of spores
D. seed dispersal
Correct Answer: B
Explanation: Embryogenesis is the process of development of an embryo from the zygote.
Q22. External fertilisation is common in
A. birds
B. reptiles
C. amphibians
D. mammals
Correct Answer: C
Explanation: In amphibians like frogs, fertilisation occurs outside the body, usually in water.
Q23. A major disadvantage of external fertilisation is
A. high energy requirement
B. less genetic variation
C. low survival rate of offspring
D. no gamete formation
Correct Answer: C
Explanation: External fertilisation exposes gametes and zygotes to environmental hazards, reducing survival chances.
Section F: Post-Fertilisation Events
Q24. The first cell of the new organism is the
A. gamete
B. embryo
C. zygote
D. sporophyte
Correct Answer: C
Explanation: Zygote is the first diploid cell formed after fertilisation.
Q25. Cleavage refers to
A. growth of embryo
B. division of zygote
C. formation of gametes
D. formation of placenta
Correct Answer: B
Explanation: Cleavage involves rapid mitotic divisions of the zygote without growth.
Q26. Implantation occurs in
A. ovary
B. oviduct
C. uterus
D. cervix
Correct Answer: C
Explanation: Implantation is the attachment of the developing embryo to the uterine wall.
Q27. Which hormone maintains pregnancy?
A. Estrogen
B. Progesterone
C. Testosterone
D. Oxytocin
Correct Answer: B
Explanation: Progesterone maintains the uterine lining and supports pregnancy.
Section G: Reproductive Strategies
Q28. Organisms producing a large number of offspring with little parental care are called
A. K-selected
B. r-selected
C. oviparous
D. viviparous
Correct Answer: B
Explanation: r-selected species produce many offspring with minimal parental care to compensate for high mortality.
Q29. Humans are examples of
A. r-selected species
B. asexual organisms
C. K-selected species
D. oviparous organisms
Correct Answer: C
Explanation: K-selected species produce fewer offspring but provide extensive parental care.
Q30. Which strategy ensures higher survival of offspring?
A. No parental care
B. External fertilisation
C. Internal fertilisation with care
D. Fragmentation
Correct Answer: C
Explanation: Internal fertilisation and parental care protect the developing young, increasing survival chances.
Section H: Conceptual & Application-Based MCQs
Q31. Asexual reproduction is advantageous in stable environments because
A. it creates variation
B. it is slow
C. offspring are well adapted
D. it involves meiosis
Correct Answer: C
Explanation: Since the environment is stable, clones well adapted to it survive efficiently.
Q32. Which process restores diploidy in sexual reproduction?
A. Meiosis
B. Mitosis
C. Fertilisation
D. Cleavage
Correct Answer: C
Explanation: Fertilisation restores the diploid chromosome number.
Q33. The term clone refers to
A. genetically different individuals
B. offspring formed by sexual reproduction
C. genetically identical individuals
D. mutated individuals
Correct Answer: C
Explanation: Clones are genetically identical individuals produced by asexual reproduction.
Q34. Which reproductive method shows maximum genetic stability?
A. Sexual reproduction
B. Asexual reproduction
C. Cross-fertilisation
D. Mutation
Correct Answer: B
Explanation: Asexual reproduction produces genetically identical offspring, ensuring genetic stability.
Q35. Meiosis is essential for sexual reproduction because it
A. increases cell size
B. reduces chromosome number
C. prevents fertilisation
D. stops variation
Correct Answer: B
Explanation: Meiosis halves the chromosome number so that diploidy is restored after fertilisation.
Q36. Which structure protects the embryo in mammals?
A. Placenta
B. Ovary
C. Testis
D. Cervix
Correct Answer: A
Explanation: Placenta facilitates nutrient exchange and protects the developing embryo.
Q37. In organisms with external fertilisation, synchronization of gamete release is necessary to
A. reduce variation
B. increase fertilisation success
C. reduce energy use
D. prevent mutation
Correct Answer: B
Explanation: Synchronised release ensures that male and female gametes meet in water.
Q38. Which event immediately follows fertilisation?
A. Gametogenesis
B. Zygote formation
C. Embryogenesis
D. Parturition
Correct Answer: B
Explanation: Fertilisation results directly in zygote formation.
Q39. Which type of reproduction is fastest?
A. Sexual reproduction
B. Asexual reproduction
C. Haplo-diplontic reproduction
D. Vivipary
Correct Answer: B
Explanation: Asexual reproduction is faster as it does not involve gamete formation or fertilisation.
Q40. Which process contributes maximum to evolution?
A. Asexual reproduction
B. Sexual reproduction
C. Fragmentation
D. Budding
Correct Answer: B
Explanation: Sexual reproduction generates variation, which drives evolution.
Section I: Assertion-Type & Higher Order Thinking
Q41. Sexual reproduction is considered superior because
A. it is rapid
B. it produces clones
C. it creates variation
D. it avoids fertilisation
Correct Answer: C
Explanation: Genetic variation improves adaptability and evolutionary potential.
Q42. Which organism shows both asexual and sexual reproduction?
A. Amoeba
B. Hydra
C. Spirogyra
D. Frog
Correct Answer: B
Explanation: Hydra reproduces asexually by budding and sexually by gamete formation.
Q43. Fertilisation occurring inside the body is called
A. external fertilisation
B. cross-fertilisation
C. internal fertilisation
D. double fertilisation
Correct Answer: C
Explanation: Internal fertilisation occurs within the female body, offering better protection to gametes.
Q44. Which factor directly affects reproductive success?
A. Body size
B. Fertilisation efficiency
C. Colour of organism
D. Habitat only
Correct Answer: B
Explanation: Successful fertilisation directly determines reproductive success.
Q45. Which is the correct sequence of sexual reproduction events?
A. Gametogenesis → Fertilisation → Embryogenesis
B. Fertilisation → Gametogenesis → Embryogenesis
C. Embryogenesis → Fertilisation → Gametogenesis
D. Cleavage → Gametogenesis → Fertilisation
Correct Answer: A
Explanation: Sexual reproduction follows a fixed sequence starting with gamete formation.
Q46. Which life cycle has only one multicellular phase?
A. Haplo-diplontic
B. Diplontic
C. Haplontic
D. All of these
Correct Answer: C
Explanation: In haplontic life cycles, the haploid phase is the only multicellular stage.
Q47. Which stage is diploid in haplontic organisms?
A. Gametophyte
B. Zygote
C. Sporophyte
D. Gamete
Correct Answer: B
Explanation: Zygote is the only diploid stage in haplontic life cycles.
Q48. Why is sexual reproduction energy-intensive?
A. Requires mitosis
B. Requires meiosis and mate finding
C. Produces spores
D. Produces clones
Correct Answer: B
Explanation: Formation of gametes and mating processes require more energy.
Q49. Which reproductive mode is most suitable for colonising new habitats quickly?
A. Sexual reproduction
B. Asexual reproduction
C. Internal fertilisation
D. K-selection
Correct Answer: B
Explanation: Asexual reproduction allows rapid multiplication in favourable conditions.
Q50. The primary biological significance of reproduction is
A. individual growth
B. repair of tissues
C. continuity of life
D. nutrition
Correct Answer: C
Explanation: Reproduction ensures continuity of species and life on Earth.
✅ Designed strictly as per NCERT syllabus
✅ Ideal for CBSE Class 12 Board Exam preparation