Primary 4 Science Semestral Assessment 2 (End of Year) Paper 1

TuitionGoWhere Practice Paper - Science Primary 4 (SA2 Version 1) - Answer Key

Subject: Science
Level: Primary 4
Paper: SA2 (Semestral Assessment 2) - Version 1
Total Marks: 60

SECTION A: Multiple-Choice Questions (28 marks)

1. Answer: (3) [2]

• Reasoning: Group A (Mould, Yeast, Bacteria) are all microorganisms (Fungi and Bacteria). Group B (Pine tree, Coconut tree, Bamboo) are all non-flowering plants (Gymnosperms/Monocots - non-flowering in primary context). Group C (Frog, Toad, Salamander) are all amphibians.
• Why others are wrong: (1) Mushroom/Yeast/Mould are fungi, not plants; Bat is a mammal, not a bird. (2) Virus is non-living; Shark is a fish, not a mammal. (4) Mushroom is fungi, not a plant; Whale is a mammal, not a fish.

2. Answer: (3) [2]

• Reasoning: The chart shows "Animals" -> "Vertebrates" -> "Mammals". A whale is a mammal, hence a vertebrate.
• Why others are wrong: (1) Not all flowering plants produce fruits (some are sterile/horticultural varieties, though typically they do; but the chart doesn't show this link explicitly as a rule). (2) Bacteria and Fungi are living things (3rd branch). (4) Mosses are under "Non-flowering" plants.

3. Answer: (2) [2]

• Reasoning: Part X is the leaf. Leaves contain chlorophyll and make food for the plant through photosynthesis.

4. Answer: (3) [2]

• Reasoning: Leaves take in carbon dioxide and give out oxygen during the day (photosynthesis). At night, they typically take in oxygen and give out carbon dioxide (respiration). The statement says "only at night", which is incorrect.

5. Answer: (4) [2]

• Reasoning: Cindy is correct: Fungi and bacteria are decomposers (break down dead organisms). Devi is correct: They are living things, so they need air, food, and water. Ali is incorrect: Bacteria reproduce by binary fission, not spores (though some form endospores, primary syllabus teaches binary fission). Bala is incorrect: Bacteria are microscopic; only some fungi (mould/mushrooms) are visible.

6. Answer: (1) [2]

• Reasoning: Mosquito has a 4-stage life cycle: Egg → Larva → Pupa → Adult (Complete Metamorphosis). Butterfly has the same 4-stage cycle: Egg → Caterpillar (Larva) → Chrysalis (Pupa) → Adult.
• Why others are wrong: Grasshopper and Cockroach have 3-stage cycles (Incomplete Metamorphosis: Egg → Nymph → Adult). Chicken has a 3-stage cycle (Egg → Chick → Adult).

7. Answer: (1) [2]

• Reasoning: Animal X: 3 body parts (Yes) -> Wings (No) -> Ant. Animal Y: 3 body parts (No) -> 8 legs (Yes) -> Spider.

8. Answer: (1) [2]

• Reasoning: The life cycle of a flowering plant: Seed germinates → Seedling grows → Adult plant matures → Flowers bloom → Pollination/Fertilisation → Fruit develops (containing seeds).

9. Answer: (4) [2]

• Reasoning: Part D is the Small Intestine. Its walls have villi to absorb digested nutrients into the bloodstream.

10. Answer: (2) [2]

• Reasoning: A magnet attracts magnetic materials (like steel/iron) via magnetic force. The paper clip is made of steel (magnetic).

11. Answer: (1) [2]

• Reasoning: Objects attracted (A, C) must be magnetic materials (Iron, Steel, Nickel, Cobalt). Objects not attracted (B, D) must be non-magnetic (Copper, Plastic, Wood, Glass). Option (1): Iron (Magnetic), Copper (Non-magnetic), Steel (Magnetic), Plastic (Non-magnetic). Matches perfectly.

12. Answer: (3) [2]

• Reasoning: Closing the switch completes the circuit. It is a series circuit. Current flows through both bulbs, so both light up.

13. Answer: (3) [2]

• Reasoning: Matter has mass and occupies space. Air, water, ice have mass and volume. A shadow is an absence of light; it has no mass and does not occupy space.

14. Answer: (2) [2]

• Reasoning: Condensation is the process where water vapour loses heat and changes into liquid water droplets (clouds). Label B points to cloud formation.

SECTION B: Open-Ended Questions (32 marks)

15. [3] (a) [2]

• Marking: 1 mark for each correct row (max 2 marks). All 3 correct = 2 marks. 1-2 correct = 1 mark.

(b) [1]

• Answer: Fungi cannot make their own food / Fungi are decomposers / Fungi reproduce by spores / Fungi do not have chlorophyll / Fungi do not have roots, stems, leaves.
• Accept any one valid difference.
• Teaching Note: Plants are food producers (photosynthesis); Fungi are decomposers (external digestion and absorption).

16. [3] (a) [1]

• Answer: Part P (Roots) absorbs water and mineral salts from the soil. / Anchors the plant firmly to the ground.
• Accept either function.

(b) [2]

• Answer: The leaves will wither / dry up / die.
• Explanation: The stem (Part Q) transports water from the roots to the leaves. When the stem is cut, water cannot reach the leaves. Without water, the leaves cannot carry out photosynthesis and will lose turgidity, causing them to wither.
• Marking: 1 mark for "wither/die", 1 mark for explanation linking cut stem -> no water transport -> leaves wither.

17. [4] (a) [1]

• Answer: Both lay eggs. / Both live in water at some stage (Guppy always, Frog lays eggs in water/tadpole stage). Best answer from flowchart: Both lay eggs.
• Teaching Note: Flowchart first question: "Does it lay eggs?" -> Yes for both Guppy and Frog.

(b) [1]

• Answer: Butterfly lays eggs but Bat does not (Bat gives birth to young alive). / Butterfly has 3 body parts (insect) but Bat has fur/hair (mammal). / Butterfly has wings (chitinous) but Bat has wings (skin membrane). Best answer from flowchart: Butterfly lays eggs, Bat does not.

(c) [1]

• Answer: Mammals have hair/fur on their bodies. / Mammals feed their young with milk. / Mammals breathe with lungs. / Mammals are warm-blooded.
• Accept any one characteristic other than "do not lay eggs".

(d) [1]

• Answer: Gills allow the guppy to take in dissolved oxygen from water / breathe underwater.

18. [4] (a) [1]

• Answer: Complete metamorphosis.
• Reasoning: 4 distinct stages (Egg, Larva, Pupa, Adult). Young (larva) looks very different from adult.

(b) [2]

• Answer: Larva (Mealworm) stage.
• Explanation: The larva is the eating and growing stage. It moults several times and consumes a large amount of food (stored grains) to store energy for the pupa stage. The adult beetle eats very little or not at all.
• Marking: 1 mark for "Larva/Mealworm", 1 mark for explanation (eating/growing stage, moults, consumes most food).

(c) [1]

• Answer: Mealworm beetle has a pupa stage (4 stages) but grasshopper has no pupa stage (3 stages: Egg, Nymph, Adult). / Mealworm beetle undergoes complete metamorphosis; grasshopper undergoes incomplete metamorphosis. / Young mealworm (larva) looks very different from adult; young grasshopper (nymph) resembles a small adult without wings.

19. [5] (a) [1]

• Answer: Part E (Large Intestine).
• Reasoning: The large intestine absorbs water and mineral salts from undigested food, forming faeces.

(b) [1]

• Answer: The digested food is absorbed into the bloodstream / blood vessels (through the villi in the small intestine).
• Teaching Note: Digestion ends in small intestine; absorption happens there.

(c) [1]

• Answer: The gullet transports food from the mouth to the stomach (by peristalsis / muscular contractions).
• Teaching Note: No digestion occurs here; it is a muscular tube for transport.

(d) [1]

• Answer: Food does not stay in the gullet long enough for digestion to occur / The gullet does not secrete digestive juices / Food moves quickly to the stomach via peristalsis.
• Teaching Note: Digestion requires time and enzymes (digestive juices).

(e) [1]

• Answer: Saliva. It contains enzymes (amylase) that digests starch into simpler sugars / moistens food for swallowing.
• Marking: Must name "Saliva" and state function (digest starch OR moisten/soften food). 1 mark total.

20. [4] (a) [1]

• Answer: Like poles repel / North pole repels North pole.
• Teaching Note: Fundamental law of magnetism: Like poles repel, Unlike poles attract.

(b) [1]

• Answer: (Drawing in diagram) The compass needle's South pole (usually white/silver) points towards the magnet's South pole. The North pole (red) points away from the magnet's South pole.
• Visual Check: Needle orientation: S (compass) facing S (magnet) -> Attraction. N (compass) facing out.
• Marking: Correct pole attraction shown (Unlike poles attract).

(c) [1]

• Answer: Stroke the magnet with another strong magnet in the same direction repeatedly (Stroking method). / Place the magnet inside a solenoid carrying direct current (Electrical method). / Stack multiple magnets together with like poles aligned.
• Accept any valid method to increase magnetic strength. (Note: Heating or hammering weakens it).

(d) [1]

• Answer:
  • Piece 1 (Left half): N (left end), S (right end / cut end).
  • Piece 2 (Right half): N (left end / cut end), S (right end).
• Reasoning: Cutting a magnet creates two smaller magnets, each with its own North and South poles. The poles at the cut ends become opposite poles (S on left piece, N on right piece).
• Marking: Both pieces correctly labelled with N and S at correct ends. 1 mark for both correct.

TOTAL: 60 MARKS