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Primary 4 Science Life Cycles Quiz

Free P4 Science Life Cycles quiz, HY3 Exam version, with questions, answers, and syllabus-aligned practice for Singapore students.

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Primary 4 Science From Real Exams Generated by Tencent HY3 Free Updated 2026-08-17

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Questions

Primary 4 Science Quiz - Life Cycles

Name: ___________________________
Class: ___________________________
Date: ___________________________
Score: ___________ / 20 marks

Duration: 40 minutes
Total Marks: 20

Instructions:

This quiz has 20 questions on the topic of Life Cycles.
Section A: Questions 1–8 (Multiple Choice, 1 mark each)
Section B: Questions 9–14 (Short Answer, 1–2 marks each)
Section C: Questions 15–20 (Diagram / Explanation, 2 marks each)
Write your answers clearly in the spaces provided.

Section A (Questions 1–8, 1 mark each)

1. Which of the following shows the correct order of stages in the life cycle of a butterfly?
A. egg → nymph → adult
B. egg → larva → pupa → adult
C. egg → pupa → larva → adult
D. egg → adult → larva → pupa

2. A grasshopper goes through incomplete metamorphosis. Which stage is missing compared to a butterfly?
A. egg
B. nymph
C. pupa
D. adult

3. What is the young stage of a frog called?
A. larva
B. nymph
C. tadpole
D. pupa

4. Which insect stage is most harmful to farmers because it eats crop leaves?
A. butterfly adult
B. caterpillar (larva)
C. grasshopper egg
D. mosquito pupa

5. Mosquito larvae and pupae live in water. They breathe using a __________.
A. gill
B. lung
C. breathing tube
D. wing

6. A frog egg develops into a tadpole. Where does this usually happen?
A. on land
B. in water
C. in soil
D. in air

7. As a grasshopper nymph grows, it sheds its skin. This process is called __________.
A. molting
B. laying eggs
C. metamorphosis
D. breathing

8. Which of the following insects does NOT have a pupa stage?
A. butterfly
B. mosquito
C. beetle
D. cockroach

Section B (Questions 9–14)

9. Name the stage labelled X in the life cycle of a butterfly: egg → X → pupa → adult. (1 mark)

10. State one similarity between the life cycle of a butterfly and a grasshopper. (1 mark)

11. A mosquito spends three stages in water: egg, larva, and pupa. State why water is important for these stages. (1 mark)

12. A frog tadpole lives in water and later becomes an adult frog. State one change that happens during its metamorphosis. (1 mark)

13. A caterpillar is the larva of a butterfly. Explain why the caterpillar stage is important for the insect's life cycle. (2 marks)

14. A grasshopper nymph looks like a small adult without wings. It molts several times. State one thing that happens each time it molts. (2 marks)

Section C (Questions 15–20, 2 marks each)

15. Study the life cycles below.

Diagram for Q15 (P4 Science)

Generated diagram for Q15.

State two differences between the life cycle of a butterfly and a grasshopper. (2 marks)

16. The bar chart below shows the number of days spent in each stage of a butterfly's life cycle.

Graph for Q16 (P4 Science)

Generated graph for Q16.

How many days does it take from egg to adult (excluding adult stage)? Show your working. (2 marks)

17. A farmer finds that caterpillars are eating the leaves of his vegetable plants. Name the insect group this larva belongs to and state why the larva is a problem. (2 marks)

18. Some people put a thin layer of oil on still water to stop mosquitoes from breeding. Explain how this helps control the mosquito population. (2 marks)

19. Complete the table below for two types of metamorphosis. (2 marks)

Type of metamorphosis	Has pupa stage?	Young resembles adult?
Complete
Incomplete

20. A cockroach grows from an egg case to a nymph, then to an adult. It molts many times. Explain what molting is and why it is needed for growth. (2 marks)

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Answers

Primary 4 Science Quiz - Life Cycles (Answer Key)

Total Marks: 20
Topic: Life Cycles (Complete vs Incomplete Metamorphosis)

Section A Answers (1 mark each)

1. B
Teaching note: Butterflies go through complete metamorphosis: egg → larva (caterpillar) → pupa (chrysalis) → adult. Option B shows the correct sequence. Common mistake: confusing with incomplete metamorphosis (no pupa).

2. C
Teaching note: Grasshopper has egg → nymph → adult (incomplete metamorphosis). Butterfly has a pupa stage; grasshopper does not. Pupa is missing.

3. C
Teaching note: The young of a frog is called a tadpole. It lives in water and later changes into an adult frog. Larva is used for insects, nymph for incomplete-metamorphosis insects.

4. B
Teaching note: Caterpillar (larva) eats leaves and can destroy crops. Adults usually sip nectar and do less crop damage.

5. C
Teaching note: Mosquito larvae and pupae live in water and use a breathing tube to reach air at the surface. They do not have gills or lungs at this stage.

6. B
Teaching note: Frog eggs are laid and hatch in water; tadpoles are aquatic.

7. A
Teaching note: Shedding skin to grow is called molting. This is seen in grasshopper nymphs.

8. D
Teaching note: Cockroach has incomplete metamorphosis (egg case → nymph → adult), so no pupa stage. Butterfly, mosquito, beetle all have pupa (complete metamorphosis).

Section B Answers

9. larva (or caterpillar) (1 mark)
Teaching note: In butterfly life cycle, after egg comes larva, then pupa, then adult.

10. Both are insects / Both go through life cycle stages / Both change appearance / Both develop wings. (1 mark, any one)
Teaching note: Similarity should show they share a life process, not a difference.

11. Water is the habitat where eggs hatch and larvae/pupae live and breathe using tubes at the surface. (1 mark)
Teaching note: Without water, mosquito young cannot survive; water provides a place to live and grow.

12. It grows legs / loses tail / develops lungs / changes from aquatic to partly land life. (1 mark, any one)
Teaching note: Metamorphosis of frog includes gaining legs and losing tail.

13. (2 marks)

1 mark: Caterpillar is the feeding/larval stage.
1 mark: It eats and grows, storing energy for pupa and adult stages.
Teaching note: Larva must eat a lot to grow; this supports later transformation.

14. (2 marks)

1 mark: It sheds its old skin (molts).
1 mark: It becomes larger / develops wings a bit more each time.
Teaching note: Nymph cannot grow inside fixed skin, so molting lets body enlarge.

Section C Answers (2 marks each)

15. (2 marks, 1 mark per difference)
Accepted differences:

Butterfly has pupa stage; grasshopper does not.
Butterfly young (larva) does not look like adult; grasshopper young (nymph) looks like adult without wings.
Butterfly larva is caterpillar; grasshopper young is nymph.
Teaching note: Diagram shows arrow sequences; use them to compare stages.

16. (2 marks)
Working: egg (4) + larva (12) + pupa (6) = 22 days.
Final: 22 days.
(1 mark for correct addition, 1 mark for correct total)
Teaching note: Read bars: egg 4, larva 12, pupa 6. Adult not counted as development stage before becoming adult.

17. (2 marks)

Insect group: butterfly (or moth) (1 mark)
Problem: larva eats leaves, damages crops/vegetables (1 mark)
Teaching note: Caterpillar is larva of butterfly/moth; it feeds on plants.

18. (2 marks)

Oil blocks air at water surface (1 mark)
Larvae/pupae cannot use breathing tube to get air, so they die / cannot breed (1 mark)
Teaching note: Mosquito young need surface air; oil prevents this.

19. (2 marks, 1 mark for two correct cells)

Type	Has pupa?	Young resembles adult?
Complete	Yes	No
Incomplete	No	Yes

Teaching note: Complete = pupa present, young different; Incomplete = no pupa, young like adult.

20. (2 marks)

Molting = shedding old skin/exoskeleton (1 mark)
Needed because skin does not stretch; molting lets cockroach grow bigger each time (1 mark)
Teaching note: Nymphs molt to increase size and gradually form adult features like wings.