Short Answer Type Questions – Topic-wise

1. Basic Concepts of ReproductionIntroduction

1. Q1. What is reproduction and why is it considered essential for living organisms? Answer: Reproduction is the biological process through which living organisms produce new individuals of their own kind. It is essential because it ensures the continuity of a species from one generation to the next and prevents its extinction.
2. Q2. Differentiate briefly between sexual and asexual reproduction. Answer: In sexual reproduction, two parents (male and female) are involved and male and female gametes fuse to form a zygote. In asexual reproduction, only one parent is involved and there is no fusion of gametes; the offspring are genetically identical to the parent.
3. Q3. What are gametes? Name the male and female gametes in humans. Answer: Gametes are special reproductive cells that take part in fertilisation. In humans, the male gamete is the sperm and the female gamete is the ovum or egg.
4. Q4. Why is reproduction not considered essential for the survival of an individual, but essential for a species? Answer: A single organism can live without reproducing if its basic life processes are functioning, so reproduction is not compulsory for its survival. However, without reproduction, no new individuals will be produced and the species will eventually die out, hence it is vital for the survival of the species.
5. Q5. List any two characteristics that offspring inherit from their parents through reproduction. Answer: Offspring inherit physical and biological traits such as eye colour, hair type, blood group, height tendency or facial features from their parents because genetic information is passed through gametes during reproduction.

2. Human Male Reproductive SystemSexual Reproduction

6. Q6. Name the main parts of the male reproductive system in humans and state their functions in brief. Answer: The main parts are testes, sperm ducts, urethra and penis. Testes produce sperms and male hormones. Sperm ducts carry sperms from testes to the urethra. The urethra is the common passage for urine and sperms, and the penis helps to deliver sperms into the female body.
7. Q7. What are testes and why are they located outside the abdominal cavity? Answer: Testes are oval reproductive organs that produce sperms. They are located in a sac called the scrotum outside the abdominal cavity to maintain a slightly lower temperature than body temperature, which is necessary for proper sperm formation.
8. Q8. Describe the structure of a sperm in short. Answer: A sperm is a microscopic, motile cell consisting of a head, a middle piece and a tail. The head contains the nucleus with genetic material, the middle piece has energy-giving structures, and the long tail helps the sperm to swim towards the egg.
9. Q9. How does the sperm reach the ovum during fertilisation in humans? Answer: During mating, sperms are released into the female reproductive tract. From the vagina, they move through the uterus and reach the oviducts using their tail movement and the fluid currents, where one sperm may fuse with the ovum.
10. Q10. State one way in which sperms and ova are similar and one way in which they are different. Answer: Both sperms and ova are gametes and contain half the number of chromosomes, carrying hereditary information. They differ in size and movement: sperms are small and motile with a tail, while ova are larger, spherical and non-motile.

3. Human Female Reproductive SystemSexual Reproduction

11. Q11. Name the main organs of the female reproductive system and mention their roles. Answer: The main organs are ovaries, oviducts (fallopian tubes), uterus, cervix and vagina. Ovaries produce eggs and hormones. Oviducts carry the egg and are the site of fertilisation. The uterus provides space and nourishment for the developing embryo. The cervix and vagina form the passage for sperms and the birth canal during delivery.
12. Q12. What is an ovum? How often is it released in human females? Answer: An ovum is the female gamete or egg cell. In human females, usually one mature ovum is released from an ovary about once every 28 days in a process known as ovulation.
13. Q13. What happens to the ovum if it is not fertilised? Answer: If the ovum is not fertilised, it does not develop into a zygote. It degenerates and, along with the thickened lining of the uterus, is expelled from the body through the vagina after some days.
14. Q14. How does the uterus help in the development of the embryo? Answer: The uterus has thick, muscular walls and a rich blood supply. The embryo gets attached to the wall of the uterus, where it is protected and receives oxygen and nutrients from the mother’s blood through the placenta till birth.
15. Q15. Why is the vagina called the birth canal? Answer: The vagina is called the birth canal because, during childbirth, the fully developed baby passes from the uterus through the cervix and vagina to the outside of the mother’s body.

4. Fertilisation and Zygote FormationCore Concepts

16. Q16. Explain the process of fertilisation in humans in two to three steps. Answer: In humans, fertilisation occurs when a sperm successfully meets an ovum in the oviduct. The sperm penetrates the outer membrane of the ovum and their nuclei fuse. This fusion of the male and female nuclei forms a single cell called the zygote.
17. Q17. What is internal fertilisation? Give two examples of animals showing this type. Answer: Internal fertilisation is fertilisation that takes place inside the body of the female. Examples: humans, cows, dogs, cats and hens.
18. Q18. What is external fertilisation? Name two animals where it occurs. Answer: External fertilisation is fertilisation that occurs outside the body of the female, usually in water. Gametes are released into the water where they fuse. Examples: frogs and many species of fish.
19. Q19. Why do animals that show external fertilisation produce a large number of gametes? Answer: In external fertilisation, many eggs and sperms are wasted because they may be eaten by predators, washed away or fail to meet. To increase the chances of some successful fertilisations, such animals produce a large number of gametes.
20. Q20. Define zygote. How does it differ from an embryo? Answer: A zygote is the single cell formed after the fusion of a sperm and an ovum. When the zygote starts dividing repeatedly to form many cells, it becomes a multicellular structure called an embryo. Thus, the zygote is the earliest stage, while the embryo is a later, multicellular stage.

5. Embryo Development, Foetus and Types of AnimalsDevelopment

21. Q21. How is an embryo formed from a zygote? Answer: After fertilisation, the zygote starts dividing by mitosis into two, then four, then many cells. This ball of cells attaches to the wall of the uterus and is called an embryo. Thus, the embryo is formed by repeated cell division of the zygote.
22. Q22. What is a foetus? At what stage of development is the embryo called a foetus? Answer: When the developing embryo inside the uterus forms all the main body parts such as limbs, head, eyes and ears, it is called a foetus. This stage is reached after the embryo has developed for some time and its organs are clearly recognisable.
23. Q23. Distinguish between oviparous and viviparous animals with one example of each. Answer: Oviparous animals lay eggs and the development of the embryo occurs inside the egg, for example, hen or frog. Viviparous animals give birth to young ones and the embryo develops inside the mother’s body, for example, humans or cow.
24. Q24. How does the embryo get nourishment inside the mother’s body? Answer: The embryo gets nourishment through a special structure called the placenta, which connects the embryo to the mother’s uterus. Nutrients and oxygen from the mother’s blood pass into the embryo’s blood, and waste products from the embryo are removed through the placenta.
25. Q25. Why do viviparous animals generally produce fewer young ones than oviparous animals produce eggs? Answer: In viviparous animals, the young ones develop inside the mother’s body and are well protected, so their chances of survival are high. Therefore, they do not need to produce many offspring. Oviparous animals lay eggs outside, where many may be destroyed, so they produce more eggs to ensure survival of some offspring.

6. Metamorphosis in FrogLife Cycle

26. Q26. Define metamorphosis and give one example from the chapter. Answer: Metamorphosis is a drastic and sudden change in the body form and habits of an animal during its life cycle. In the chapter, the life cycle of a frog is an example, where the tadpole larva changes into an adult frog.
27. Q27. Write the stages in the life cycle of a frog in correct sequence. Answer: The stages are: Adult frog → eggs in water → tadpoles (larva) with tail and gills → growing tadpoles with developing limbs and shrinking tail → adult frog with lungs and no tail.
28. Q28. How is the larval form of a frog different from an adult frog in terms of habitat and breathing? Answer: The larval form, called a tadpole, lives only in water and breathes through gills like fish. An adult frog can live both in water and on land and breathes mainly through lungs, and also through moist skin.
29. Q29. Why is metamorphosis in frog considered a good example of adaptation to two habitats? Answer: The frog starts life as a tadpole adapted to an aquatic habitat, with gills and a tail for swimming. Later, it metamorphoses into an adult frog adapted to both land and water, with lungs and limbs. This shows adaptation to two different habitats during its life cycle.
30. Q30. How does the tadpole gradually change into an adult frog? Answer: As the tadpole grows, its hind legs and then front legs appear. The tail becomes shorter and finally disappears. At the same time, lungs develop and gills disappear. Gradually, the tadpole transforms into an adult frog that can live on land and in water.

7. Asexual Reproduction – Amoeba, Hydra and YeastAsexual Mode

31. Q31. What is asexual reproduction? Mention any two advantages of this mode. Answer: Asexual reproduction is reproduction in which only one parent is involved and no fusion of gametes occurs. Two advantages are: it is a quick method that helps organisms multiply rapidly, and it does not require the presence of a mate, which is useful when individuals are far apart.
32. Q32. Explain the process of binary fission in Amoeba. Answer: In binary fission, the nucleus of the Amoeba first divides into two. Then the cytoplasm divides, forming two daughter Amoebae. Each daughter cell receives one nucleus and some cytoplasm. Both the new Amoebae grow to full size and repeat the process.
33. Q33. How does Hydra reproduce by budding? Answer: In Hydra, a small outgrowth or bud appears on the body due to repeated cell division at a particular site. The bud grows and develops tentacles and a mouth. When it becomes fully mature, it detaches from the parent Hydra and lives as an independent organism.
34. Q34. Describe budding in yeast in short. Answer: Yeast reproduces by budding. A small bulb-like outgrowth appears on the parent cell. The nucleus divides and one nucleus moves into the bud. The bud grows and may remain attached, forming a chain, or separate to form a new yeast cell.
35. Q35. Why are offspring produced by asexual reproduction called clones? Answer: Offspring produced by asexual reproduction are called clones because they are genetically identical to the parent and to one another. They inherit exactly the same set of genes since there is no mixing of genetic material from two parents.

8. Key Terms and DefinitionsImportant Concepts

36. Q36. Define the terms: (a) embryo (b) placenta. Answer: (a) An embryo is the early stage of development of the baby formed from the dividing zygote. (b) The placenta is a special tissue connection between the mother and the developing embryo which allows the exchange of nutrients, oxygen and waste products.
37. Q37. What are viviparous animals? Name any two such animals. Answer: Viviparous animals are animals that give birth to young ones. Examples: humans and cows.
38. Q38. What are oviparous animals? Explain with two examples. Answer: Oviparous animals are animals that lay eggs, and the development of the embryo occurs inside the egg. Examples: birds like hen, and amphibians like frog.
39. Q39. State the role of the umbilical cord in human development. Answer: The umbilical cord is a tube that connects the foetus to the placenta. It carries oxygen and nutrient-rich blood from the mother to the foetus and returns waste products from the foetus to the mother’s blood for removal.
40. Q40. What is meant by the term “life cycle” of an organism? Answer: The life cycle of an organism is the sequence of stages an organism passes through from the beginning of its life (as a new individual) until it reproduces and forms new individuals of its own kind.

9. Mixed Exam-Oriented Short Answer QuestionsExam Practice

41. Q41. How do both parents contribute to the inheritance of traits in the offspring? Answer: The father contributes his genetic information through the sperm, and the mother contributes hers through the ovum. During fertilisation, the nuclei of the sperm and ovum fuse, combining genes from both parents. As a result, the child shows characteristics inherited from both mother and father.
42. Q42. Why is it important for students to understand the difference between internal and external fertilisation? Answer: Understanding this difference helps students relate reproduction to the habitat and survival strategies of animals. It also explains why some animals produce many eggs while others produce fewer offspring, an important concept for CBSE exam questions and higher classes.
43. Q43. Explain in short how the NCERT textbook describes reproduction in Amoeba and Hydra. Answer: The NCERT textbook explains that Amoeba reproduces by binary fission, where the parent cell splits into two identical daughter cells. Hydra reproduces by budding, where a small bud grows on the parent’s body, develops tentacles and then separates as a new individual.
44. Q44. Why are labelled diagrams important in the chapter “Reproduction in Animals”? Answer: Labelled diagrams of the human male and female reproductive systems, life cycle of frog, and asexual reproduction in Amoeba and Hydra help in visual understanding, and they are frequently asked in exams for 2–3 mark questions. Neat diagrams with proper labelling can fetch full marks.
45. Q45. In what way do the revision questions from this chapter help in CBSE Class 8 exam preparation? Answer: The revision questions cover all NCERT-based concepts such as definitions, processes, diagrams and differences. Practising them regularly improves conceptual clarity, writing skills and speed, which are crucial for scoring well in CBSE Class 8 Science examinations.
46. Q46. Why is the environment inside the uterus ideal for the growth of the embryo? Answer: The uterus has soft, protective walls and a rich blood supply. It keeps the embryo cushioned and at a constant temperature. Through the placenta, the embryo receives a continuous supply of nutrients and oxygen, making the environment ideal for its growth.
47. Q47. How do animals ensure the survival of their young ones after birth or hatching? Answer: Many animals protect, feed and care for their young after birth or hatching. For example, birds keep their chicks warm and bring food, and mammals feed their young with milk. Such parental care increases the chances of survival of the young ones.
48. Q48. Give reasons why frogs are considered both aquatic and terrestrial animals with respect to their life cycle. Answer: Frogs lay eggs in water and their tadpole stage lives entirely in water, breathing through gills. The adult frog, however, can live on land as well as in water and breathes through lungs. Therefore, their life cycle shows both aquatic and terrestrial phases.
49. Q49. How can studying asexual reproduction help us understand rapid multiplication of microorganisms? Answer: In asexual reproduction, organisms like Amoeba and bacteria multiply quickly by dividing into two. Understanding this helps us know how infections spread rapidly and why proper hygiene and cleanliness are important to control harmful microorganisms.
50. Q50. Summarise in a few lines what you have learnt in the chapter “Reproduction in Animals”. Answer: In this chapter, we learn about the importance of reproduction, structure and functions of human male and female reproductive systems, fertilisation, development of the zygote into an embryo and foetus, oviparous and viviparous animals, metamorphosis in frog, and basic asexual reproduction in Amoeba, Hydra and yeast. These ideas form the foundation for understanding reproduction in higher classes.