Primary 3 Science Systems Quiz

Primary 3 Science Quiz - Systems - Answer Key

Total Marks: 40

Section A: Multiple Choice (10 marks)

Common Mistakes (Section A):

• Q4: Students may choose "Snake" as snakes also have scales. However, the most direct answer linking scales to a fish is (b). Accept either fish or snake as both have scales, but the intended answer is (b) Goldfish as it is the classic fish example. Marking note: Award mark for (d) Snake as well since both are correct.
• Q8: Students may confuse the functions of roots and stems. Roots absorb water; stems transport it.

Section B: Short Answer (10 marks)

11. (2 marks — 1 mark each)

Any two of the following:

• Skeletal system
• Muscular system
• Digestive system
• Respiratory system
• Circulatory system
• Nervous system

Accept any two correct body systems.

12. (2 marks)

Sample acceptable answer: The stem carries water and food to other parts of the plant, but the root absorbs water and minerals from the soil.

Accept any valid functional difference. Do not accept differences in appearance only (e.g., "the stem is long, the root is short").

13. (2 marks — 1 mark each)

Any two of: (a) They live on land and in water. (b) They lay eggs (usually in water / jelly-like eggs without hard shells). (c) They have moist skin. (d) Young amphibians breathe through gills; adults breathe through lungs and skin.

14. (2 marks — 1 mark each)

Any two of: (a) Fins (for swimming / balancing) (b) Gills (for breathing in water) (c) Scales (for protecting the body) (d) Streamlined body (for moving easily through water)

15. (2 marks)

The heart pumps blood to all parts of the body. (2 marks)

Accept: "The heart pumps blood around the body." Do not accept just "It pumps blood" without specifying what is pumped and where (1 mark only if incomplete).

Section C: Open-Ended (15 marks)

16. (3 marks)

(a) Mammals [1 mark]

(b) The bat is not a bird because [1 mark for any valid reason below]:

• It does not have feathers (it has hair/fur).
• It gives birth to live young (birds lay eggs).
• It feeds its young with milk (birds do not).

[1 mark for a second valid reason OR for a clear explanation linking the characteristic to the classification rule]

Minimum acceptable: "The bat has fur, not feathers." (2 marks)

Common Mistake: Students may say "the bat cannot fly as well as the eagle" — this does not explain classification and earns 0 marks.

17. (3 marks)

(a) Water [1 mark]

Accept: "Water and minerals" — still 1 mark.

(b) The plant needs water [1 mark] to make food in the leaves / to stay alive and not wilt / for the leaves to carry out photosynthesis [1 mark].

Accept any valid reason linking water to a life process of the plant.

18. (3 marks)

(a) Any one of: Digestive system, Respiratory system, Skeletal system, Circulatory system, Nervous system, Muscular system [1 mark]

(b) Humans: Humans eat food / get food by eating other living things / consume food through the mouth [1 mark]

Plants: Plants make their own food in the leaves using sunlight / photosynthesis [1 mark]

Accept: "Plants make food using sunlight, water and air."

19. (3 marks)

(a) Any two of [2 marks — 1 mark each]: (i) They have dry, scaly skin. (ii) They lay eggs with leathery shells / lay eggs on land. (iii) They breathe through lungs. (iv) They are cold-blooded.

(b) The snake moves by slithering / crawling on its belly / using its muscles to push against the ground. [1 mark]

Accept: "It slithers." or "It uses its body muscles to move."

20. (3 marks)

(a) The digestive system provides digested food / nutrients / energy-giving substances to the body. [1 mark]

(b) The respiratory system provides oxygen / air (specifically oxygen) to the body. [1 mark]

(c) We need both because food gives us energy [½ mark] and oxygen is needed to release this energy [½ mark]. OR: We need nutrients to grow and repair our body, and oxygen to stay alive and release energy from food. [1 mark]

Accept: "Food gives us energy and oxygen helps us use the energy." (1 mark)

Common Mistake: Students may say "we need food and air to survive" without explaining the relationship. Award ½ mark for a vague but partially correct answer.

Mark Summary: