🧬 Biology · Topic 9 of 10
Start with the study notes on Reproduction in Living Things (definitions, examples and a quick revision), then work through 60 practice questions, each with the correct answer and a clear explanation of why it is right. When you are ready, take this topic as an interactive quiz to test yourself.
Topic overview
Reproduction is the process by which living things produce new individuals of their own kind. It keeps a species going from one generation to the next.
Asexual: one parent, identical offspring · Sexual: two parents, varied offspring
Asexual reproduction needs only one parent, with no joining of reproductive cells. The young are identical to the parent.
The parent cell splits into two.
Example: Amoeba and bacteria.
The parent splits into many new individuals at once.
Example: Plasmodium, the malaria parasite.
A small outgrowth (bud) grows on the parent and separates as a new individual.
Example: Yeast and Hydra.
The body breaks into pieces, and each piece grows into a new organism.
Example: Spirogyra (an alga).
Tiny, light spores with a hard coat are carried by the wind. They survive harsh conditions, and grow when conditions improve.
Example: Bread mould (Rhizopus) and ferns.
New plants grow from roots, stems or leaves, instead of seeds.
Examples:
Some simple animals can regrow lost parts, and even a whole body from a piece.
Example: Hydra, Planaria and starfish.
Sexual reproduction involves two parents. A male reproductive cell and a female reproductive cell (gametes) join together. This joining is fertilisation, and it forms a zygote.
Sperm + Egg → Zygote → Embryo → Young one
Remember: Sexual reproduction creates variation. The young are not identical to their parents, which helps a species survive changes in its environment.
Example: In humans, the baby grows in the mother's womb and gets food and oxygen through the placenta. The developing baby is called an embryo, and later a foetus.
Metamorphosis is a big change in body form as a young animal grows into an adult.
Egg → Tadpole → Adult frog
A tadpole lives in water and breathes with gills. It gradually grows legs and lungs.
Egg → Caterpillar (larva) → Pupa (chrysalis) → Adult butterfly
Remember: Humans, cats and birds don't go through metamorphosis. Their young look like small adults (direct development).
A clone is an exact genetic copy of another organism.
Example: Dolly the sheep, born in 1996, was the first mammal cloned from an adult cell.
| Misconception | Correct understanding |
|---|---|
| Asexual offspring are different from their parent. | Asexual offspring are identical to the parent; sexual offspring vary. |
| All animals give birth to live young. | Birds, reptiles, fish and frogs lay eggs (they are oviparous). |
| Every egg will hatch. | Only a fertilised egg can develop; the eggs we usually eat won't hatch. |
| A tadpole is just a small frog. | A tadpole has gills and a tail; it changes completely by metamorphosis. |
| Plants reproduce only by seeds. | Many also reproduce by vegetative parts, such as potato eyes and stem cuttings. |
How does Amoeba reproduce?
By binary fission.
How does yeast reproduce?
By budding.
What is the main advantage of sexual reproduction?
It produces variation, which helps the species survive change.
What is formed when a sperm joins an egg?
A zygote.
Why do frogs lay so many eggs?
Fertilisation is external and many eggs are eaten or lost.
Is a hen oviparous or viviparous?
Oviparous: it lays eggs.
Name the four stages in a butterfly's life.
Egg, caterpillar (larva), pupa and adult.
Which plant grows new plants from its leaves?
Bryophyllum.
Key takeaway: Asexual reproduction is quick and makes identical copies; sexual reproduction joins two parents' cells and makes varied young that help a species survive.
Notes written by Velnov for Class 6–8 students, following the topics of the NCERT science syllabus.
Q1. easy
The process by which living organisms produce new individuals of their own kind is called:
Answer: A — Reproduction
Reproduction ensures the continuation of a species from one generation to the next. Without it, a species would disappear when its members die.
Q2. easy
The two main types of reproduction are:
Answer: A — Sexual and asexual
Asexual reproduction involves a single parent and no gametes; sexual reproduction involves two parents and the fusion of male and female gametes.
Q3. medium
Reproduction that involves only ONE parent and no fusion of gametes is called:
Answer: A — Asexual reproduction
In asexual reproduction the offspring are produced from a single parent and are genetically identical to it. It is common in simple organisms and plants.
Q4. medium
Reproduction that involves TWO parents and the fusion of gametes is called:
Answer: A — Sexual reproduction
Sexual reproduction combines genetic material from a male and a female parent, so the offspring show variation and are not identical to either parent.
Q6. medium
The cell formed by the fusion of a male and a female gamete is called a:
Answer: A — Zygote
The zygote is the first cell of a new individual. It divides repeatedly to form an embryo, which grows into the offspring.
Q8. medium
In Amoeba, the parent cell simply splits into two. This method of asexual reproduction is called:
Answer: A — Binary fission
In binary fission, the nucleus divides first, then the cell splits into two daughter cells, each a complete new Amoeba.
Q10. medium
In yeast and Hydra, a small outgrowth develops and separates to form a new individual. This is called:
Answer: A — Budding
A bud grows on the parent, develops into a small individual, and then detaches (or, in a colony, stays attached). It is a common form of asexual reproduction.
Q12. medium
Fungi like Rhizopus (bread mould) and ferns reproduce by producing:
Answer: A — Spores
Spores are tiny, light reproductive units covered by a hard protective coat. They are carried by wind and germinate into new individuals when conditions are right.
Q14. medium
The production of new plants from vegetative parts such as roots, stems and leaves is called:
Answer: A — Vegetative propagation
Vegetative propagation is a form of asexual reproduction in plants. Potato, ginger, sugarcane, rose and Bryophyllum all reproduce this way.
Q16. medium
An ADVANTAGE of sexual reproduction is that:
Answer: A — It produces variation, helping the species adapt and survive
By combining features from two parents, sexual reproduction creates variety. This variation helps some individuals survive changes in the environment.
Q18. medium
The transfer of pollen from the anther to the stigma is called:
Answer: A — Pollination
Pollination precedes fertilisation. It may occur within one flower (self-pollination) or between two flowers of the same kind (cross-pollination).
Q20. medium
Animals that lay eggs are called:
Answer: A — Oviparous
Birds, reptiles, amphibians, fish and insects are oviparous - the young develop inside eggs laid outside the mother's body.
Q21. medium
Animals that give birth to LIVE young are called:
Answer: A — Viviparous
Most mammals, including humans, cows and dogs, are viviparous. The young develop inside the mother and are born alive.
Q23. medium
Fertilisation that takes place INSIDE the female body, as in humans and birds, is called:
Answer: A — Internal fertilisation
In internal fertilisation, the sperm are deposited inside the female, where they fuse with the egg. Fewer eggs are needed because the chances of survival are higher.
Q25. medium
The female reproductive cell in animals is the:
Answer: A — Egg (ovum)
The egg is larger than the sperm and non-motile, containing food for the early embryo. Eggs are produced in the female organs called the ovaries.
Q27. medium
The development of an embryo into a young one that resembles the adult is called:
Answer: A — Direct development
In direct development, the newborn looks like a small version of the adult - as in humans, cats and birds - and simply grows larger over time.
Q29. medium
The life cycle of a frog passes through which stages?
Answer: A — Egg, tadpole (larva), and adult frog
A frog lays eggs in water. Each egg hatches into a tadpole with gills and a tail, which gradually grows legs and lungs and becomes an adult frog.
Q31. medium
The ability of some animals to grow back a lost body part is called:
Answer: A — Regeneration
Hydra, Planaria and starfish can regrow lost parts. If a Planaria is cut into pieces, each piece may grow into a complete new organism.
Q33. medium
Cloning is the production of an organism that is:
Answer: A — An exact genetic copy of another organism
A clone is genetically identical to the single parent. Dolly the sheep, born in 1996, was the first mammal cloned from an adult body cell.
Q35. medium
Why do fish and frogs lay a very LARGE number of eggs?
Answer: A — Many eggs are eaten or fail to develop, so a large number ensures some survive
With external fertilisation and no parental care, most eggs and young are lost to predators or unfavourable conditions. Laying many eggs improves the chance that some grow into adults.
Q37. medium
Which of these reproduces by SEEDS?
Answer: A — Mango tree
Flowering plants such as mango reproduce sexually through seeds formed after pollination and fertilisation. Amoeba, bacteria and yeast reproduce asexually.
Q39. medium
The young one inside the mother's body develops into a baby and is born. The developing young is called:
Answer: A — An embryo (later a foetus)
After fertilisation, the zygote divides to form an embryo, which develops organs and grows into a foetus before being born as a baby.
Q41. medium
Self-pollination occurs when pollen is transferred:
Answer: A — From the anther to the stigma of the same flower or another flower on the same plant
Self-pollination keeps the parent's characters but gives little variation. Cross-pollination between two plants of the same kind creates more variety.
Q43. medium
A tadpole breathes through gills, but an adult frog breathes through:
Answer: A — Lungs and moist skin
During metamorphosis the tadpole's gills are replaced by lungs. The adult frog also exchanges gases through its moist skin, especially underwater.
Q45. medium
Which of these plants reproduces through its LEAVES?
Answer: A — Bryophyllum
Buds form in the notches along the margins of Bryophyllum leaves. When they fall on moist soil, each grows into a new plant.
Q47. medium
Which of these animals undergoes metamorphosis?
Answer: A — Frog and butterfly
Frogs and butterflies pass through a larval stage very different from the adult. Mammals develop directly, with the young resembling the adult from birth.
Q49. medium
Budding in yeast is best described as:
Answer: A — A small bud growing on the parent cell and separating to form a new yeast
A tiny bud appears on the yeast cell, grows, and pinches off as a new individual. Under good conditions, chains of buds can form rapidly.
Q51. medium
The eggs of birds have a hard shell that:
Answer: A — Protects the developing embryo and prevents it from drying out
The calcium-rich shell shields the embryo from injury and moisture loss while allowing air to pass through tiny pores for the embryo to breathe.
Q53. medium
Layering is a method of propagation in which:
Answer: A — A branch is bent to the ground and covered with soil until it grows roots
In layering, a low branch is buried while still attached to the parent. It develops roots, after which it is cut off and grown as a separate plant. Jasmine and grapes are propagated this way.
Q55. medium
Why do farmers often prefer vegetative propagation for fruit plants?
Answer: A — The new plants are identical to the parent and bear fruit sooner than seed-grown plants
Because the offspring are genetically identical, the desirable fruit quality is preserved exactly, and the plants mature and fruit faster than those raised from seed.
Q57. medium
Which of these is NOT a method of asexual reproduction?
Answer: A — Fertilisation of gametes
Fertilisation, the fusion of gametes, is the key step of sexual reproduction. Binary fission, budding, fragmentation and spore formation are all asexual.
Q59. medium
A caterpillar changes into a butterfly inside a resting stage called the:
Answer: A — Pupa (chrysalis)
During the pupa stage the caterpillar's body is completely reorganised into that of the adult butterfly. It appears still on the outside while dramatic changes happen within.
Q5. hard
The male and female reproductive cells are together called:
Answer: A — Gametes
The male gamete (sperm in animals, pollen in plants) fuses with the female gamete (egg or ovule). Their union begins the development of a new individual.
Q7. hard
The fusion of the male and female gametes to form a zygote is called:
Answer: A — Fertilisation
Fertilisation is the central event of sexual reproduction. It restores the full number of chromosomes and combines features from both parents.
Q9. hard
Plasmodium, the malarial parasite, reproduces by splitting into MANY individuals at once. This is called:
Answer: A — Multiple fission
In multiple fission, the nucleus divides many times inside the parent, and each part surrounds itself with cytoplasm, so many offspring form together.
Q11. hard
In Spirogyra, the filament breaks into pieces and each piece grows into a new plant. This is called:
Answer: A — Fragmentation
Fragmentation is the breaking of the body into fragments, each of which grows into a complete organism. It is seen in Spirogyra and many other algae.
Q13. hard
The hard protective covering of a spore helps it to:
Answer: A — Survive unfavourable conditions such as high heat or lack of moisture
The tough coat lets spores remain dormant through drought or extreme temperatures. When conditions improve, they germinate, which is why mould appears quickly on stale food.
Q15. hard
An ADVANTAGE of asexual reproduction is that:
Answer: A — A single parent can reproduce quickly, and offspring are identical to it
Asexual reproduction is fast and needs only one parent, so favourable characters are passed on unchanged. Its drawback is the lack of variation.
Q17. hard
In flowering plants, the male reproductive part is the stamen and the female part is the:
Answer: A — Pistil (carpel)
The stamen produces pollen; the pistil, with its stigma, style and ovary, receives the pollen and holds the ovules that become seeds.
Q19. hard
After fertilisation in a flower, the ovule develops into a seed and the ovary develops into a:
Answer: A — Fruit
The fertilised ovule becomes the seed, and the ovary wall thickens into the fruit that protects the seeds and often helps in their dispersal.
Q22. hard
Fertilisation that takes place OUTSIDE the female body, as in frogs and fish, is called:
Answer: A — External fertilisation
In external fertilisation, eggs and sperm are released into water, where they meet. Large numbers of eggs are produced because many are lost or eaten.
Q24. hard
The male reproductive cell in animals is the:
Answer: A — Sperm
Sperms are small and motile, with a tail for swimming. They are produced in the male reproductive organs called the testes.
Q26. hard
Sperms are produced in the male organs called the testes, and eggs are produced in the female organs called the:
Answer: A — Ovaries
The two ovaries release eggs, while the testes make sperm. These reproductive organs produce the gametes needed for sexual reproduction.
Q28. hard
The transformation of a larva into an adult through distinct stages is called:
Answer: A — Metamorphosis
In metamorphosis, the young form is very different from the adult. A frog develops from a tadpole, and a butterfly from a caterpillar, through clear stages.
Q30. hard
The complete metamorphosis of a butterfly passes through which four stages?
Answer: A — Egg, larva (caterpillar), pupa, adult
The butterfly's egg hatches into a caterpillar, which feeds and grows, then forms a pupa (chrysalis) inside which it transforms into the adult butterfly.
Q32. hard
If a Hydra is cut into several pieces, each piece can grow into a new Hydra. This shows:
Answer: A — Regeneration, which can act as a form of reproduction
Regeneration in simple animals like Hydra and Planaria can increase their numbers, blurring the line between repair and asexual reproduction.
Q34. hard
Dolly the sheep, the first cloned mammal, was created in:
Answer: A — 1996
Scientists in Scotland cloned Dolly in 1996 from a single adult cell, proving that a complete animal could be produced without normal sexual reproduction.
Q36. hard
Mammals produce FEWER offspring than fish because:
Answer: A — Internal fertilisation and parental care give each young a much higher chance of survival
The young of mammals develop safely inside the mother and are cared for after birth, so far fewer offspring are needed to keep the population steady.
Q38. hard
Which of these is an example of asexual reproduction in a MULTICELLULAR animal?
Answer: A — Budding in Hydra
Hydra, though multicellular, reproduces asexually by budding. A bud grows on its body and detaches as a new Hydra.
Q40. hard
In humans, the developing baby gets its food and oxygen from the mother through the:
Answer: A — Placenta
The placenta connects the developing baby to the wall of the mother's womb, supplying nutrients and oxygen and carrying away wastes.
Q42. hard
Cross-pollination is usually brought about by agents such as:
Answer: A — Insects, wind, water and birds
Bright petals, scent and nectar attract insects and birds, while wind and water carry light pollen from one plant to another.
Q44. hard
Why is variation produced by sexual reproduction important for a species?
Answer: A — It helps some individuals survive changes in the environment, aiding the species' long-term survival
When conditions change - a new disease, climate shift or predator - varied individuals mean some are likely to cope and survive, so the species endures.
Q46. hard
Which method of reproduction produces offspring GENETICALLY IDENTICAL to the parent?
Answer: A — Asexual reproduction
Because only one parent and no gamete fusion are involved, asexual offspring inherit exactly the same genes as the parent - they are natural clones.
Q48. hard
A hen's egg that is not fertilised will:
Answer: A — Not develop into a chick
Only a fertilised egg contains an embryo that can develop into a chick. Unfertilised eggs, like those we usually eat, will never hatch.
Q50. hard
Which statement correctly compares asexual and sexual reproduction?
Answer: A — Asexual needs one parent and gives identical offspring; sexual needs two parents and gives varied offspring
The key difference lies in the number of parents and the presence of variation. Asexual is quick and reliable; sexual is slower but generates the variation that fuels adaptation.
Q52. hard
Grafting, used to grow fruit trees, is a method of:
Answer: A — Vegetative propagation, joining a cutting of one plant onto the rooted stem of another
In grafting, a shoot (scion) of a desirable plant is joined to the root system (stock) of another. It combines good fruit quality with a strong root, and the offspring keep the parent's traits.
Q54. hard
Which of these correctly matches an organism with its method of reproduction?
Answer: A — Amoeba - binary fission; Hydra - budding; Spirogyra - fragmentation; Rhizopus - spores
Each simple organism has its typical asexual method: Amoeba splits by binary fission, Hydra and yeast bud, Spirogyra fragments, and Rhizopus forms spores.
Q56. hard
Spore formation is an advantageous method of reproduction because spores:
Answer: A — Are produced in large numbers, are light, and can survive harsh conditions
Being numerous and light, spores are easily dispersed by wind over great distances, and their tough coats let them wait out bad conditions before germinating.
Q58. hard
Which overall statement about reproduction is CORRECT?
Answer: A — Reproduction continues a species; it may be asexual (one parent, identical offspring) or sexual (two parents, varied offspring)
This sums up the topic: asexual methods such as fission, budding, fragmentation and spore formation are quick and produce clones, while sexual reproduction through gametes and fertilisation produces the variation essential for survival.
Q60. hard
Which of these organisms can reproduce by BOTH sexual and asexual methods?
Answer: A — Hydra - by budding (asexual) and by gametes (sexual)
Hydra usually buds when conditions are good, but can also reproduce sexually by forming eggs and sperm. Many simple organisms can switch methods depending on conditions.