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Primary 6 PSLE Science Systems Quiz

Free P6 PSLE Science Systems quiz, HY3 Exam version, with questions, answers, and PSLE-focused practice for Singapore students.

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Primary 6 PSLE Science From Real Exams Generated by Tencent HY3 Free Updated 2026-08-17

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Questions

Primary 6 PSLE Science Quiz - Systems

Name: ___________________________
Class: ___________________________
Date: ___________________________
Score: _______ / 40

Duration: 50 minutes
Total Marks: 40
Topic: Systems (Digestive, Respiratory, Circulatory, Interaction of Forces, Interactions within Environment as systems)

Instructions:

Answer all 20 questions.
Section A: Multiple-choice (1 mark each). Section B: Short answer (2 marks each). Section C: Structured explanation (2 marks each).
Write your answers clearly in the spaces provided.

Section A (Questions 1–5)

Circle the correct letter. (1 mark each)

1. Which of the following is NOT a part of the human digestive system?
A) Stomach
B) Lung
C) Small intestine
D) Mouth

2. In the circulatory system, what is the main job of red blood cells?
A) Fight germs
B) Carry oxygen
C) Digest food
D) Send nerve signals

3. A force is best described as a:
A) Type of energy
B) Push or a pull
C) Form of matter
D) Living thing

4. Which force pulls objects towards the Earth?
A) Magnetic force
B) Frictional force
C) Gravitational force
D) Elastic spring force

5. In a food chain, plants are called producers because they:
A) Eat other animals
B) Make their own food using sunlight
C) Break down dead leaves
D) Hunt for prey

Section B (Questions 6–15)

Answer in the spaces provided. (2 marks each)

6. Name two organs in the respiratory system and state one function of each.

7. Explain why friction is useful when we walk.

8. A spring is stretched. What type of force does the spring exert and in which direction?

9. State the energy pathway in a simple food chain: Sun → grass → rabbit. What role does the rabbit play?

10. What is a population? Give one example.

11. Describe one structural adaptation of a fish that helps it obtain oxygen underwater.

12. The diagram below shows a simple circuit system.

Diagram for Q12 (P6 Science)

Generated diagram for Q12.

If the switch is closed, what happens to the bulb? Why?

13. Give one negative impact of man on the environment and one positive impact.

14. Weight is the gravitational force acting on an object. If a book has a mass of 1 kg, what force pulls it down? (Use g ≈ 10 N/kg)

15. Decomposers are important in a community. What do they do and why is this helpful?

Section C (Questions 16–20)

Answer in the spaces provided. (2 marks each)

16. A student pushes a stationary toy car. State two possible effects of this force on the toy car.

17. Explain how the digestive system and circulatory system work together to give the body energy.

18. A pond community has frogs, insects, pond plants and bacteria. Classify each as producer, consumer, or decomposer.

19. A rubber band is used to launch a paper pellet. Describe the force involved and how it changes the pellet's motion.

20. Some organisms die when their habitat becomes too hot and dry. Give two other things that may happen to organisms in an unfavourable environment.

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Answers

Primary 6 PSLE Science Quiz - Systems (Answer Key)

Total Marks: 40
Topic: Systems

Section A (1 mark each)

1. B
Teaching note: The lung is part of the respiratory system, not the digestive system. Digestive system parts include mouth, stomach, small intestine (and others). Common mistake: confusing breathing with eating.

2. B
Teaching note: Red blood cells contain haemoglobin that binds oxygen in the lungs and carries it to all body cells via the circulatory system.

3. B
Teaching note: A force is a push or a pull that can move, stop, or change the shape of an object. It is not energy or matter.

4. C
Teaching note: Gravitational force is the pull of the Earth on objects, giving them weight. Magnetic and elastic are contact/field forces; friction opposes motion.

5. B
Teaching note: Producers (like plants) make their own food by photosynthesis using sunlight, forming the start of the energy flow.

Section B (2 marks each)

6. (2m)
Answer: Two organs: e.g. nose (breathes in air / filters air), lungs (gas exchange: oxygen in, carbon dioxide out).
Marking: 1m per organ + function.
Teaching: Respiratory system brings in oxygen and removes CO₂; examples include nose, trachea, lungs.

7. (2m)
Answer: Friction between our shoes and ground prevents slipping, allowing us to push backward and move forward.
Marking: 1m friction opposes slipping, 1m explains forward movement.
Teaching: Frictional force acts opposite to motion; useful for grip.

8. (2m)
Answer: Elastic spring force; it pulls back (towards original length / opposite to stretch).
Marking: 1m type, 1m direction.
Teaching: Stretched elastic exerts a restoring force opposite to the stretch.

9. (2m)
Answer: Sun → grass (producer) → rabbit (consumer). Rabbit is a consumer (eats producer).
Marking: 1m pathway, 1m role.
Teaching: Energy flows from Sun to producer to consumer.

10. (2m)
Answer: A population is a group of the same kind of organisms living together. Example: a school of fish / flock of birds.
Marking: 1m definition, 1m example.

11. (2m)
Answer: Fish have gills that extract oxygen from water.
Marking: 1m structure, 1m function.
Teaching: Gills are structural adaptations for underwater respiration.

12. (2m)
Answer: Bulb lights up because closing the switch completes the circuit, allowing current to flow.
Marking: 1m lights, 1m reason (complete circuit).
Visual: Series circuit with cell, switch closed, bulb lit.

13. (2m)
Answer: Negative: deforestation / pollution; Positive: reforestation / conservation.
Marking: 1m each.

14. (2m)
Answer: Weight = m × g = 1 kg × 10 N/kg = 10 N downward.
Marking: 1m formula/substitution, 1m answer with unit.
Teaching: Weight is gravitational force; use g = 10 N/kg at P6.

15. (2m)
Answer: Decomposers break down dead organisms; this returns nutrients to soil/water for producers.
Marking: 1m action, 1m benefit.

Section C (2 marks each)

16. (2m)
Answer: May start moving; may speed up / change direction / change shape. (Any two)
Marking: 1m per correct effect.

17. (2m)
Answer: Digestive system breaks food into nutrients absorbed into blood; circulatory system transports nutrients/glucose to cells for respiration to release energy.
Marking: 1m digestion absorption, 1m transport to cells for energy.

18. (2m)
Answer: Pond plants = producer; insects & frogs = consumers; bacteria = decomposer.
Marking: 1m correct grouping, 1m all classified.

19. (2m)
Answer: Elastic spring force from stretched rubber band; it pushes pellet forward (starts motion / launches).
Marking: 1m force type, 1m effect on motion.

20. (2m)
Answer: They may adapt and survive; they may move to another place.
Marking: 1m per point. (Die is given; other two from syllabus.)