Class 8 Science – Chapter 9: Reproduction in Animals

🔬 Introduction

Reproduction is the biological process by which living organisms produce new individuals of the same species. It ensures the continuity of life on Earth.

There are two main types of reproduction in animals:

Sexual Reproduction
Asexual Reproduction

🧬 1. Sexual Reproduction

📌 What is Sexual Reproduction?

It involves two parents (male and female). They produce special cells called gametes:

Male gamete → Sperm
Female gamete → Egg (Ovum)

When sperm and egg fuse, a zygote is formed.

🧪 Fertilisation

Fertilisation is the process of fusion of sperm and egg.

Types of Fertilisation:

1. Internal Fertilisation

Occurs inside the female body
Examples: Humans, cows, dogs, hens
After fertilisation, the zygote develops into an embryo

2. External Fertilisation

Occurs outside the body, usually in water
Examples: Frogs, fish
Female lays eggs → Male releases sperm on them

🧫 Development of Embryo

Zygote → Embryo → Foetus → Young one
The embryo develops inside the uterus in humans
The stage when body parts are formed is called foetus

🐣 Viviparous and Oviparous Animals

Type	Description	Examples
Viviparous	Give birth to young ones	Humans, cow
Oviparous	Lay eggs	Hen, frog

🧪 2. Asexual Reproduction

📌 What is Asexual Reproduction?

Only one parent is involved
No fertilisation occurs
Offspring are identical to parent

🦠 Types of Asexual Reproduction

1. Binary Fission (in Amoeba)

One cell divides into two
Example: Amoeba

2. Budding (in Hydra)

A small outgrowth (bud) develops into a new individual
Example: Hydra

🐸 Metamorphosis

A process where a larva transforms into an adult
Example: Frog
Stages: Egg → Tadpole → Adult frog

📚 Important Keywords

Reproduction: Producing new individuals
Fertilisation: Fusion of gametes
Zygote: Fertilised egg
Embryo: Early stage of development
Foetus: Later stage with body parts
Metamorphosis: Transformation process

✅ Summary

Reproduction is essential for survival of species
Sexual reproduction involves two parents and fertilisation
Asexual reproduction involves one parent
Animals reproduce in different ways (egg-laying or giving birth)
Some animals undergo metamorphosis

Class 8 Science – Chapter 9: Reproduction in Animals (Detailed Explanation ~2000 words)

🌱 Introduction to Reproduction

Reproduction is one of the most important characteristics of living organisms. Every organism, whether plant or animal, has the ability to produce new individuals of its own kind. This process ensures that life continues on Earth. Without reproduction, species would become extinct over time.

In animals, reproduction is not just about producing young ones; it also involves the transfer of genetic information from parents to offspring. This helps maintain the identity of the species and also brings variation, which is important for evolution.

Animals reproduce mainly in two ways:

Sexual Reproduction
Asexual Reproduction

🧬 Sexual Reproduction in Animals

Sexual reproduction involves two parents, a male and a female. Each parent produces special reproductive cells called gametes.

Male gamete → Sperm
Female gamete → Ovum (Egg)

These gametes are formed in reproductive organs:

Male: Testes
Female: Ovaries

🔬 Fertilisation

Fertilisation is the process in which the male gamete (sperm) fuses with the female gamete (egg) to form a zygote.

The zygote is the first cell of a new individual. It contains genetic material from both parents.

🔍 Types of Fertilisation

There are two types of fertilisation in animals:

1. Internal Fertilisation

Fertilisation occurs inside the body of the female
Common in land animals

Examples:

Humans
Dogs
Cows
Hens

Process:

Male releases sperm inside female body
Sperm travels to meet egg
Fertilisation occurs → zygote forms
Zygote develops into embryo inside uterus

Advantages:

Higher chances of survival of embryo
Protection from external environment

2. External Fertilisation

Fertilisation occurs outside the body
Usually in water

Examples:

Frogs
Fish

Process:

Female lays eggs in water
Male releases sperm over eggs
Fertilisation occurs in water

Disadvantages:

Many eggs are lost or eaten
Less protection → fewer survive

🧫 Development After Fertilisation

Once fertilisation occurs, the zygote begins to divide repeatedly. This process is called cell division.

🔄 Stages of Development:

Zygote – Single cell formed after fertilisation
Embryo – Early stage of development
Foetus – Later stage when body parts are formed
Young one – Fully developed organism

👶 Development in Humans

Fertilisation occurs in female body
Zygote travels to uterus
It attaches to uterine wall
Develops into embryo → foetus
After about 9 months, baby is born

The embryo gets nourishment from the mother through a special structure called the placenta.

🐣 Oviparous and Viviparous Animals

Animals differ in how they give birth to young ones.

1. Oviparous Animals (Egg-laying)

Lay eggs
Embryo develops outside the body

Examples:

Hen
Frog
Lizard
Snake

2. Viviparous Animals (Give birth)

Give birth to young ones
Embryo develops inside mother’s body

Examples:

Humans
Cow
Dog

🐸 Metamorphosis

Metamorphosis is a biological process in which an animal undergoes a drastic change in form during its life cycle.

Example: Frog

Stages:

Egg
Tadpole (has tail, lives in water)
Adult frog (lungs, legs, lives on land and water)

🧪 Asexual Reproduction in Animals

Asexual reproduction involves only one parent. There is no fusion of gametes.

Features:

Only one parent required
Offspring are identical (clones)
Fast process

🦠 Types of Asexual Reproduction

1. Binary Fission (Amoeba)

One cell divides into two equal parts
Nucleus divides first, then cytoplasm

Example:

Amoeba

2. Budding (Hydra)

A small bud grows on parent body
It develops into new individual
Later separates from parent

Example:

Hydra

🧠 Importance of Reproduction

Reproduction is essential because:

It ensures continuity of species
It maintains population
It passes genetic traits to next generation
It creates variation (in sexual reproduction)
It helps in evolution and survival

⚖️ Difference Between Sexual and Asexual Reproduction

Feature	Sexual Reproduction	Asexual Reproduction
Parents	Two	One
Gametes	Present	Absent
Fertilisation	Occurs	Does not occur
Variation	Present	Absent
Speed	Slow	Fast
Examples	Humans, animals	Amoeba, Hydra

🧩 Special Points to Remember

Fertilisation forms a zygote
Internal fertilisation gives more protection
External fertilisation needs water
Viviparous animals give birth
Oviparous animals lay eggs
Metamorphosis involves drastic changes
Asexual reproduction produces identical offspring

📚 Conclusion

Reproduction in animals is a fascinating and essential biological process that ensures the survival of species. From simple organisms like Amoeba to complex animals like humans, different methods of reproduction are used depending on the environment and level of organisation.

Sexual reproduction introduces variation, which is important for evolution and adaptation, while asexual reproduction allows rapid multiplication in simpler organisms. Understanding these processes helps us appreciate the diversity of life and the continuity of species on Earth.

Here are 80 MCQs from Class 8 Science Chapter 9 – Reproduction in Animals (with answers):

✅ MCQs (1–20)

Reproduction is the process of: A) Respiration
B) Growth
C) Producing new individuals
D) Digestion
Ans: C
The male gamete is called: A) Egg
B) Ovum
C) Sperm
D) Embryo
Ans: C
The female gamete is called: A) Sperm
B) Ovum
C) Zygote
D) Foetus
Ans: B
Fusion of sperm and egg is called: A) Reproduction
B) Fertilisation
C) Budding
D) Division
Ans: B
The product of fertilisation is: A) Embryo
B) Foetus
C) Zygote
D) Egg
Ans: C
Internal fertilisation occurs: A) Outside body
B) Inside female body
C) Inside male body
D) In water
Ans: B
External fertilisation occurs: A) Inside body
B) In uterus
C) Outside body
D) In lungs
Ans: C
Which animal shows external fertilisation? A) Dog
B) Cow
C) Frog
D) Human
Ans: C
Which is viviparous animal? A) Hen
B) Frog
C) Human
D) Snake
Ans: C
Which is oviparous animal? A) Cow
B) Dog
C) Hen
D) Human
Ans: C
The embryo develops into: A) Zygote
B) Foetus
C) Sperm
D) Egg
Ans: B
The stage with developed body parts is: A) Embryo
B) Foetus
C) Zygote
D) Gamete
Ans: B
Amoeba reproduces by: A) Budding
B) Binary fission
C) Fertilisation
D) Fragmentation
Ans: B
Hydra reproduces by: A) Budding
B) Fission
C) Fertilisation
D) Spore
Ans: A
Asexual reproduction involves: A) Two parents
B) One parent
C) Gametes
D) Fertilisation
Ans: B
Offspring in asexual reproduction are: A) Different
B) Identical
C) Bigger
D) Smaller
Ans: B
The uterus is present in: A) Male
B) Female
C) Both
D) None
Ans: B
The testes produce: A) Eggs
B) Sperm
C) Embryo
D) Foetus
Ans: B
The ovaries produce: A) Sperm
B) Egg
C) Zygote
D) Foetus
Ans: B
Fertilisation leads to formation of: A) Egg
B) Sperm
C) Zygote
D) Embryo
Ans: C

✅ MCQs (21–40)

Which process involves drastic change in form? A) Growth
B) Metamorphosis
C) Respiration
D) Digestion
Ans: B
Tadpole is stage of: A) Fish
B) Frog
C) Dog
D) Cow
Ans: B
Fertilisation in humans is: A) External
B) Internal
C) Both
D) None
Ans: B
Egg-laying animals are: A) Viviparous
B) Oviparous
C) Both
D) None
Ans: B
Animals giving birth are: A) Oviparous
B) Viviparous
C) Both
D) None
Ans: B
Zygote divides to form: A) Gamete
B) Embryo
C) Egg
D) Sperm
Ans: B
Embryo develops in: A) Liver
B) Heart
C) Uterus
D) Brain
Ans: C
The process of cell division after fertilisation: A) Growth
B) Development
C) Both
D) None
Ans: C
Amoeba is: A) Multicellular
B) Unicellular
C) Both
D) None
Ans: B
Binary fission produces: A) One cell
B) Two cells
C) Many cells
D) None
Ans: B
Budding is seen in: A) Amoeba
B) Hydra
C) Frog
D) Human
Ans: B
External fertilisation needs: A) Air
B) Water
C) Soil
D) Heat
Ans: B
Which has highest survival rate? A) External fertilisation
B) Internal fertilisation
C) Both
D) None
Ans: B
Sperm is: A) Male gamete
B) Female gamete
C) Zygote
D) Embryo
Ans: A
Egg is: A) Male gamete
B) Female gamete
C) Zygote
D) Foetus
Ans: B
Zygote is formed by: A) Division
B) Fertilisation
C) Budding
D) Growth
Ans: B
Foetus stage occurs: A) Early
B) Middle
C) Late
D) None
Ans: C
Hydras are: A) Plants
B) Animals
C) Bacteria
D) Fungi
Ans: B
Variation occurs in: A) Asexual reproduction
B) Sexual reproduction
C) Both
D) None
Ans: B
Clones are: A) Different
B) Identical
C) Bigger
D) Smaller
Ans: B

✅ MCQs (41–60)

Frog fertilisation is: A) Internal
B) External
C) Both
D) None
Ans: B
Fish reproduce by: A) Internal fertilisation
B) External fertilisation
C) Budding
D) Fission
Ans: B
Placenta provides: A) Oxygen
B) Food
C) Protection
D) All
Ans: D
Human gestation period is: A) 3 months
B) 6 months
C) 9 months
D) 12 months
Ans: C
Embryo attaches to: A) Heart
B) Uterus
C) Brain
D) Liver
Ans: B
Sperm is produced in: A) Ovary
B) Testes
C) Uterus
D) Brain
Ans: B
Egg is produced in: A) Testes
B) Ovary
C) Uterus
D) Brain
Ans: B
Amoeba reproduces quickly because: A) Sexual reproduction
B) Asexual reproduction
C) Slow division
D) None
Ans: B
Budding forms: A) Same organism
B) New organism
C) Dead cell
D) None
Ans: B
Tadpole breathes through: A) Lungs
B) Gills
C) Skin
D) Nose
Ans: B
Adult frog breathes through: A) Gills
B) Lungs
C) Only skin
D) None
Ans: B
Metamorphosis occurs in: A) Human
B) Frog
C) Cow
D) Dog
Ans: B
Zygote is: A) Single cell
B) Tissue
C) Organ
D) System
Ans: A
Fertilisation occurs in: A) Male
B) Female
C) Both
D) None
Ans: B
Offspring resemble parents due to: A) Food
B) Genes
C) Water
D) Air
Ans: B
Amoeba divides into: A) 1
B) 2
C) 3
D) 4
Ans: B
Bud forms in: A) Amoeba
B) Hydra
C) Frog
D) Fish
Ans: B
Egg shell protects: A) Adult
B) Embryo
C) Sperm
D) Foetus
Ans: B
Internal fertilisation occurs in: A) Fish
B) Frog
C) Human
D) All
Ans: C
External fertilisation occurs in: A) Cow
B) Dog
C) Frog
D) Human
Ans: C

✅ MCQs (61–80)

Reproduction ensures: A) Death
B) Survival of species
C) Digestion
D) Respiration
Ans: B
Asexual reproduction produces: A) Variation
B) No variation
C) Mutation
D) None
Ans: B
Sexual reproduction produces: A) No variation
B) Variation
C) Same offspring
D) None
Ans: B
Hydra develops from: A) Egg
B) Bud
C) Sperm
D) Zygote
Ans: B
Amoeba reproduction is: A) Sexual
B) Asexual
C) Both
D) None
Ans: B
Fertilisation forms: A) Embryo
B) Zygote
C) Foetus
D) Egg
Ans: B
Uterus is part of: A) Male
B) Female
C) Both
D) None
Ans: B
Testes are part of: A) Male
B) Female
C) Both
D) None
Ans: A
Ovary is part of: A) Male
B) Female
C) Both
D) None
Ans: B
Internal fertilisation increases: A) Risk
B) Survival
C) Loss
D) None
Ans: B
External fertilisation decreases: A) Eggs
B) Survival
C) Water
D) None
Ans: B
Tadpole changes into: A) Fish
B) Frog
C) Bird
D) Dog
Ans: B
Metamorphosis is: A) Small change
B) Big change
C) No change
D) Slow change
Ans: B
Embryo stage comes after: A) Foetus
B) Zygote
C) Adult
D) Egg
Ans: B
Foetus stage comes after: A) Zygote
B) Embryo
C) Egg
D) Adult
Ans: B
Egg contains: A) Embryo
B) Foetus
C) Adult
D) None
Ans: A
Zygote divides by: A) Respiration
B) Cell division
C) Digestion
D) Movement
Ans: B
Asexual reproduction is: A) Fast
B) Slow
C) Both
D) None
Ans: A
Sexual reproduction is: A) Fast
B) Slow
C) Both
D) None
Ans: B
Reproduction is essential for: A) Growth
B) Survival
C) Movement
D) Digestion
Ans: B

Here are 10 Case Study Questions from Class 8 Science Chapter 9 – Reproduction in Animals (with answers):

📘 Case Study 1: Human Reproduction

Riya learned that in humans, fertilisation takes place inside the female body. The zygote formed develops into an embryo and later into a foetus inside the uterus.

Questions:

Where does fertilisation occur in humans?
What is a zygote?
Where does the embryo develop?
What is the stage after embryo called?

Answers:

Inside the female body (uterus)
Fertilised egg
In the uterus
Foetus

📘 Case Study 2: Frog Reproduction

During rainy season, frogs lay eggs in water. The male releases sperm over the eggs, and fertilisation occurs outside the body.

Questions:

What type of fertilisation occurs in frogs?
Why do frogs lay eggs in water?
What is formed after fertilisation?
Name one more animal with this type of fertilisation.

Answers:

External fertilisation
Because fertilisation occurs in water
Zygote
Fish

📘 Case Study 3: Amoeba Reproduction

Amoeba is a unicellular organism that reproduces by splitting into two identical cells.

Questions:

What type of reproduction occurs in Amoeba?
What is binary fission?
How many cells are formed?
Are offspring identical or different?

Answers:

Asexual reproduction
Division of one cell into two
Two cells
Identical

📘 Case Study 4: Hydra Budding

Hydra reproduces by developing a small outgrowth on its body, which later detaches and grows into a new individual.

Questions:

What type of reproduction is this?
What is the outgrowth called?
Is fertilisation involved?
Name another organism that reproduces asexually.

Answers:

Asexual reproduction
Bud
No
Amoeba

📘 Case Study 5: Metamorphosis in Frog

A frog starts its life as a tadpole which lives in water and breathes through gills. Later it develops legs and lungs.

Questions:

What is this process called?
What does tadpole breathe through?
What does adult frog breathe through?
Name the stages of frog life cycle.

Answers:

Metamorphosis
Gills
Lungs
Egg → Tadpole → Adult

📘 Case Study 6: Oviparous Animals

A hen lays eggs, and the chick develops inside the egg outside the mother’s body.

Questions:

What type of animals are these?
Where does embryo develop?
Give one more example.
Is fertilisation internal or external in hens?

Answers:

Oviparous
Inside egg
Snake
Internal fertilisation

📘 Case Study 7: Viviparous Animals

A cow gives birth to a calf. The young one develops inside the mother’s body.

Questions:

What type of animals are these?
Where does development occur?
Give one more example.
Which organ supports development?

Answers:

Viviparous
Inside mother’s body
Human
Uterus

📘 Case Study 8: Internal Fertilisation Advantage

Animals like humans and dogs have internal fertilisation, where the embryo develops safely inside the body.

Questions:

What is internal fertilisation?
Name two animals with this type.
What is one advantage?
Is survival rate high or low?

Answers:

Fertilisation inside female body
Human, Dog
Protection of embryo
High

📘 Case Study 9: External Fertilisation Disadvantage

Fish release thousands of eggs in water, but only a few survive.

Questions:

Why do fish produce many eggs?
What type of fertilisation occurs?
Why is survival rate low?
Where does fertilisation occur?

Answers:

To ensure some survive
External fertilisation
Eggs are unprotected
Outside body

📘 Case Study 10: Asexual vs Sexual Reproduction

Rahul observed that Amoeba produces identical offspring, while humans produce offspring with variations.

Questions:

What type of reproduction occurs in Amoeba?
What type occurs in humans?
Which one produces variation?
Which one is faster?

Answers:

Asexual
Sexual
Sexual reproduction
Asexual reproduction

Here are 20 Short Answer Questions with Answers from

Class 8 Science – Chapter 9: Reproduction in Animals

✏️ Short Answer Questions (1–20)

1. What is reproduction?

Answer: Reproduction is the process by which living organisms produce new individuals of their own kind.

2. What are gametes?

Answer: Gametes are reproductive cells. Male gamete is sperm and female gamete is ovum (egg).

3. What is fertilisation?

Answer: Fertilisation is the fusion of male and female gametes to form a zygote.

4. What is a zygote?

Answer: A zygote is the fertilised egg formed after fusion of sperm and ovum.

5. What is an embryo?

Answer: Embryo is the early stage of development formed from repeated division of the zygote.

6. What is a foetus?

Answer: Foetus is the later stage of embryo when body parts are formed.

7. Define internal fertilisation.

Answer: Internal fertilisation is the fusion of gametes inside the female body.

8. Give two examples of animals with internal fertilisation.

Answer: Humans and dogs.

9. Define external fertilisation.

Answer: External fertilisation is the fusion of gametes outside the body, usually in water.

10. Give two examples of animals with external fertilisation.

Answer: Frogs and fish.

11. What are oviparous animals?

Answer: Animals that lay eggs are called oviparous animals.

12. Give two examples of oviparous animals.

Answer: Hen and frog.

13. What are viviparous animals?

Answer: Animals that give birth to young ones are called viviparous animals.

14. Give two examples of viviparous animals.

Answer: Human and cow.

15. What is metamorphosis?

Answer: Metamorphosis is a process of drastic transformation in body form during life cycle.

16. Give an example of metamorphosis.

Answer: Frog.

17. What is asexual reproduction?

Answer: Asexual reproduction is reproduction involving only one parent without fertilisation.

18. Name two organisms that reproduce asexually.

Answer: Amoeba and Hydra.

19. What is binary fission?

Answer: Binary fission is a type of asexual reproduction where one organism divides into two equal parts.

20. What is budding?

Answer: Budding is a type of asexual reproduction in which a new organism grows from a small outgrowth on the parent body.

Here are 20 Long Answer Questions with Answers from

Class 8 Science – Chapter 9: Reproduction in Animals

🧠 Long Answer Questions (1–20)

1. Explain the process of reproduction in animals.

Answer:
Reproduction is the biological process by which animals produce young ones of their own kind. It ensures continuity of species. Animals reproduce mainly in two ways: sexual and asexual reproduction. In sexual reproduction, male and female gametes fuse to form a zygote, which develops into an embryo and then a new individual. In asexual reproduction, only one parent is involved, and offspring are identical to the parent. Examples include Amoeba (binary fission) and Hydra (budding).

2. Describe sexual reproduction in animals.

Answer:
Sexual reproduction involves two parents, a male and a female. The male produces sperms and the female produces eggs. These gametes fuse during fertilisation to form a zygote. The zygote undergoes repeated cell division to form an embryo, which later develops into a foetus and finally into a young one. This type of reproduction results in variation among offspring.

3. What is fertilisation? Explain its types.

Answer:
Fertilisation is the fusion of male and female gametes to form a zygote. It is of two types:

Internal fertilisation: Occurs inside the female body (e.g., humans, dogs).
External fertilisation: Occurs outside the body, usually in water (e.g., frogs, fish).
Internal fertilisation provides protection to the embryo, while external fertilisation has lower survival rates.

4. Explain the development of embryo in humans.

Answer:
After fertilisation, the zygote divides repeatedly to form an embryo. The embryo travels to the uterus and attaches to its wall. It continues to grow and develop body parts, becoming a foetus. The foetus receives nourishment from the mother through the placenta. After about nine months, the fully developed baby is born.

5. Differentiate between oviparous and viviparous animals.

Answer:
Oviparous animals lay eggs, and the development of embryo occurs outside the body (e.g., hen, frog). Viviparous animals give birth to young ones, and the embryo develops inside the mother’s body (e.g., humans, cow). Viviparous animals provide better protection and nourishment to the developing embryo.

6. Explain asexual reproduction in animals with examples.

Answer:
Asexual reproduction involves only one parent and no fertilisation. Offspring are identical to the parent. It is a faster method of reproduction. Examples include:

Amoeba: reproduces by binary fission
Hydra: reproduces by budding

7. Describe binary fission in Amoeba.

Answer:
Binary fission is a type of asexual reproduction in which a single Amoeba divides into two identical cells. First, the nucleus divides into two parts, followed by division of cytoplasm. Each new cell grows into a complete Amoeba. This process is rapid and produces identical offspring.

8. Describe budding in Hydra.

Answer:
In Hydra, a small outgrowth called a bud develops on the parent body due to repeated cell division. The bud grows gradually and develops into a new individual. Once fully developed, it detaches from the parent and lives independently.

9. What is metamorphosis? Explain with example.

Answer:
Metamorphosis is a process in which an organism undergoes drastic changes in its body form during development. Example: Frog.
Stages include: Egg → Tadpole → Adult frog
The tadpole has gills and a tail, while the adult frog has lungs and legs.

10. Explain the life cycle of a frog.

Answer:
The frog undergoes metamorphosis. The female lays eggs in water. These eggs hatch into tadpoles, which breathe through gills and have tails. Gradually, legs develop, the tail shortens, and lungs develop. Finally, the tadpole transforms into an adult frog.

11. Write advantages of internal fertilisation.

Answer:

Fertilisation occurs inside the body
Embryo gets protection
Higher chances of survival
Less wastage of gametes
Development occurs in a controlled environment

12. Write disadvantages of external fertilisation.

Answer:

Occurs outside the body
Eggs may be eaten by predators
Environmental conditions affect survival
Large number of eggs required
Low survival rate

13. Explain the role of placenta.

Answer:
Placenta is a special organ that develops in the uterus during pregnancy. It connects the mother and the developing foetus. It supplies oxygen and nutrients to the foetus and removes waste products. It plays a vital role in the growth and development of the baby.

14. What are the main differences between sexual and asexual reproduction?

Answer:
Sexual reproduction involves two parents and fertilisation, producing variation in offspring. Asexual reproduction involves one parent without fertilisation and produces identical offspring. Sexual reproduction is slower, while asexual reproduction is faster.

15. Explain why reproduction is important.

Answer:
Reproduction is essential for the survival of species. It ensures continuity of life, maintains population, and transfers genetic traits from parents to offspring. It also helps in variation and evolution, which are important for adaptation.

16. What is the role of cell division in reproduction?

Answer:
Cell division is important for growth and development of the zygote. After fertilisation, the zygote divides repeatedly to form an embryo. This division increases the number of cells and helps in formation of tissues and organs.

17. How does Amoeba reproduce? Explain briefly.

Answer:
Amoeba reproduces asexually by binary fission. The nucleus divides first, followed by division of cytoplasm. This results in formation of two identical daughter cells, each growing into a new Amoeba.

18. How does Hydra reproduce? Explain briefly.

Answer:
Hydra reproduces by budding. A small bud forms on its body due to cell division. The bud grows and develops into a new Hydra. After maturation, it detaches from the parent and becomes independent.

19. Explain the stages of human development after fertilisation.

Answer:
After fertilisation, a zygote is formed. It divides repeatedly to form an embryo. The embryo implants in the uterus and develops into a foetus. The foetus grows and develops body parts. After about nine months, a fully developed baby is born.

20. Why do animals reproduce by different methods?

Answer:
Animals reproduce by different methods depending on their environment and level of organisation. Aquatic animals use external fertilisation due to water availability, while land animals use internal fertilisation for protection. Simpler organisms reproduce asexually for rapid multiplication, while complex organisms use sexual reproduction for variation and survival

Here is a Complete 80 Marks Question Paper for

📘 Class 8 Science – Chapter 9: Reproduction in Animals

📝 Question Paper (Time: 3 Hours | Maximum Marks: 80)

Section A – MCQs (1 × 20 = 20 Marks)

Choose the correct option:

Reproduction is the process of:
a) Digestion
b) Growth
c) Producing young ones
d) Respiration
Male gamete is called:
a) Ovum
b) Sperm
c) Zygote
d) Embryo
Fertilisation is:
a) Division
b) Fusion of gametes
c) Growth
d) Development
Zygote is formed after:
a) Growth
b) Fertilisation
c) Division
d) Respiration
Internal fertilisation occurs in:
a) Frog
b) Fish
c) Human
d) All
External fertilisation occurs in:
a) Cow
b) Dog
c) Frog
d) Human
Animals that lay eggs are:
a) Viviparous
b) Oviparous
c) Both
d) None
Amoeba reproduces by:
a) Budding
b) Binary fission
c) Fertilisation
d) Spore
Hydra reproduces by:
a) Fission
b) Budding
c) Fragmentation
d) Fertilisation
Metamorphosis occurs in:
a) Dog
b) Human
c) Frog
d) Cow
Embryo develops into:
a) Zygote
b) Foetus
c) Egg
d) Sperm
Foetus stage is:
a) Early
b) Middle
c) Later
d) None
Testes produce:
a) Egg
b) Sperm
c) Zygote
d) Foetus
Ovaries produce:
a) Sperm
b) Egg
c) Embryo
d) Foetus
Asexual reproduction involves:
a) Two parents
b) One parent
c) Gametes
d) Fertilisation
Tadpole breathes through:
a) Lungs
b) Gills
c) Skin
d) Nose
Variation occurs in:
a) Asexual reproduction
b) Sexual reproduction
c) Both
d) None
Placenta provides:
a) Oxygen
b) Food
c) Protection
d) All
Amoeba is:
a) Multicellular
b) Unicellular
c) Both
d) None
Reproduction ensures:
a) Growth
b) Survival of species
c) Movement
d) Digestion