Primary 4 Science Semestral Assessment 2 (End of Year) Paper 5

TuitionGoWhere Practice Paper - Science Primary 4 (SA2 Version 5) - Answer Key

Subject: Science
Level: Primary 4
Paper: SA2 (Semestral Assessment 2) - Version 5
Total Marks: 100

SECTION A: Multiple-Choice Questions (56 marks)

Diversity (Living and Non-Living Things)

1 Answer: (1) Mushroom, moss, fern [2 marks]

Explanation: Living things need air, food, and water; they grow, reproduce, and respond to changes. Mushrooms (fungi), mosses, and ferns (plants) are all living things. Clouds, rivers, rocks, robots, cars, computers, shadows, reflections, and light are non-living things.

Common mistake: Students may think mushrooms are non-living because they don't move, or that clouds are living because they "move" and "grow".

2 Answer: (3) Item C – Non-Living Things → Natural [2 marks]

Explanation:

• Item A (Mushroom) is a fungus → Living Things → Fungi (not Non-Living)
• Item B (Wooden chair) is man-made from wood → Non-Living Things → Man-made (not Living Things)
• Item C (River stone) is a natural non-living thing → Non-Living Things → Natural ✓
• Item D (Moss) is a plant → Living Things → Plants (not Non-Living)

3 Answer: (3) Bala and Devi only [2 marks]

Explanation:

• Ali: Incorrect. Plants are living things but cannot move from place to place.
• Bala: Correct. All living things need air, food, and water.
• Cindy: Incorrect. Not all living things lay eggs (e.g., mammals give birth, plants produce seeds/spores).
• Devi: Correct. All living things grow and respond to changes.

4 Answer: (2) Part X: Attracts pollinators | Part Y: Protects the seeds [2 marks]

Explanation:

• Part X is the flower. Its function is to attract pollinators (bees, butterflies) for pollination.
• Part Y is the fruit. Its function is to protect the seeds inside and aid in seed dispersal.

Common mistake: Students may confuse flower function with "makes food" (that's the leaf) or fruit function with "disperses seeds" (fruit protects seeds; dispersal is a separate process).

5 Answer: (2) They make their own food. [2 marks]

Explanation: Fungi (mushrooms, yeast, mould) are decomposers. They cannot make their own food (no chlorophyll). They feed on dead or decaying matter by secreting digestive enzymes and absorbing nutrients. They reproduce by spores and cannot move from place to place.

6 Answer: (2) Yeast [2 marks]

Explanation: Following the flowchart:

• Yeast is a living thing → Yes
• Does it make its own food? → No (fungi are decomposers)
• Does it reproduce by spores? → Yes (yeast reproduces by budding/spores) → Classified as Fungi.

Moss and fern are plants (make own food). Bacteria are micro-organisms but not classified as fungi in this simplified flowchart.

7 Answer: (2) Cat | Rose plant | Sand | Air [2 marks]

Explanation:

• W: Needs air/food/water, reproduces, responds, grows, does NOT make own food → Animal (Cat) ✓
• X: All characteristics including makes own food → Plant (Rose plant) ✓
• Y: No living characteristics → Non-living (Sand) ✓
• Z: No living characteristics → Non-living (Air) ✓

Option (1): Mushroom doesn't make own food. Option (3): Bacteria are living. Option (4): Moss makes own food.

Diversity (Materials)

8 Answer: (2) They are good conductors of heat. [2 marks]

Explanation: All metals are good conductors of heat and electricity. However, not all metals are magnetic (only iron, nickel, cobalt, steel). Metals sink in water (high density). Metals are opaque, not transparent.

9 Answer: (2) Conductors of electricity | Insulators of electricity [2 marks]

Explanation: Group A (copper, iron, steel, aluminium) are all metals and good conductors of electricity. Group B (plastic, wood, rubber, glass) are non-metals and insulators of electricity.

Note: Not all Group A are magnetic (copper, aluminium are not). Not all Group B are non-magnetic (some may contain iron). Flexibility varies within groups.

10 Answer: (4) Material S [2 marks]

Explanation: A ruler must be rigid (not bend) to measure accurately. Material S did not bend at all when the same weight was applied, making it the most rigid and suitable for a ruler.

11 Answer: (2) Water has a definite volume but no definite shape. [2 marks]

Explanation: Water is a liquid. Liquids have a definite volume (cannot be compressed easily) but no definite shape (take the shape of their container). Solids have both definite shape and volume. Gases have neither.

12 Answer: (2) B [2 marks]

Explanation:

• A (Evaporation): Water gains heat, changes from liquid to gas.
• B (Condensation): Water vapour loses heat to surroundings, changes from gas to liquid (clouds form).
• C (Precipitation): Water falls as rain.
• D (Collection): Water gathers in water bodies.

Condensation is the process where water vapour loses heat.

13 Answer: (1) Metal is a better conductor of heat than plastic. [2 marks]

Explanation: The metal spoon handle felt hotter because metal conducts heat away from the hot water faster than plastic. Heat travels quickly through metal (good conductor) but slowly through plastic (poor conductor/insulator).

14 Answer: (3) Plastic food wrap [2 marks]

Explanation:

• Raincoat: Waterproof, flexible, but NOT transparent.
• Glass window: Waterproof, transparent, but NOT flexible.
• Plastic food wrap: Waterproof, flexible, AND transparent ✓
• Rubber boots: Waterproof, flexible, but NOT transparent.

15 Answer: (4) D [2 marks]

Explanation: A shower curtain needs to be:

• Waterproof (to keep water in) → D: Yes
• Flexible (to hang and move) → D: Yes
• Transparent (to let light in) → D: Yes
• Strong: Not critical for shower curtain → D: No (acceptable)

Material A: Not flexible. Material B: Not transparent. Material C: Not waterproof.

Systems (Plant Parts and Functions)

16 Answer: (1) The roots will not receive food and will die. [2 marks]

Explanation: Food-carrying tubes (phloem) transport food made in the leaves to all parts of the plant, including the roots. If these tubes are removed in a ring (girdling), food cannot reach the roots, and they will die. Water-carrying tubes (xylem) transport water upward from roots to leaves.

17 Answer: (3) Root [2 marks]

Explanation: Roots anchor the plant firmly to the ground, absorb water and minerals from the soil, and store food. Stems support the plant and transport substances. Leaves make food. Flowers are for reproduction.

18 Answer: (2) Water-carrying tubes [2 marks]

Explanation: The red-coloured water was absorbed by the roots and transported up the stem to the flowers. Water-carrying tubes (xylem) transport water and dissolved minerals from roots to all parts of the plant. Food-carrying tubes transport food from leaves downward.

19 Answer: (1) Part X (Stomata): Takes in carbon dioxide | Part Y (Chloroplasts): Traps light energy [2 marks]

Explanation:

• Stomata (Part X) are

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TuitionGoWhere Practice Paper - Science Primary 4 (Answer Key)

TuitionGoWhere Exam Practice (AI)

Subject: Science
Level: Primary 4
Paper: SA2 (Semestral Assessment 2) - Version 5
Total Marks: 100

SECTION A: Multiple-Choice Questions (56 marks)

SECTION B: Open-Ended Questions (44 marks)

Question 29 (3 marks)

a) Classify the three organisms into the correct groups in the table below. [1]

b) State one characteristic of fungi that is different from plants. [1] Fungi cannot make their own food / Fungi feed on dead or decaying matter / Fungi reproduce by spores (while plants reproduce by seeds/spores but make own food).

c) The butterfly lays eggs on the leaves of the fern. Explain why the butterfly does this. [1] So that the caterpillars (larvae) have food (fern leaves) to eat immediately after hatching.

Question 30 (2 marks)

a) Based on the diagram, state the function of Part A. [1] Part A (Gullet/Oesophagus): Transports food from the mouth to the stomach. / Connects mouth to stomach.

b) No digestion takes place in Part A. Explain why. [1] The gullet has no digestive juices / enzymes. Its walls are muscular for peristalsis (pushing food down), not for digestion.

Question 31 (3 marks)

a) In the diagram above, label the water-carrying tubes and food-carrying tubes. [1] (Label the larger outer tubes as "Water-carrying tubes (Xylem)" and smaller inner tubes as "Food-carrying tubes (Phloem)")

b) The food-carrying tubes were removed in a ring around the stem. After a few days, the stem above the cut became swollen. Explain why. [2] Food made by the leaves is transported down the food-carrying tubes. When these tubes are cut, food cannot be transported past the cut and accumulates above it, causing swelling.

Question 32 (2 marks)

a) State the function of the stomata on the underside of leaves. [1] To take in carbon dioxide and release oxygen / for gaseous exchange / to allow transpiration (release water vapour).

b) Explain why most stomata are found on the underside of leaves rather than the upper side. [1] To reduce water loss through transpiration, as the underside is shaded from direct sunlight and cooler.

Question 33 (3 marks)

The diagram below shows a set-up to investigate a property of light.

Image pending generation: diagram for Q33.

a) What property of light is being investigated? [1] Reflection of light / Light reflects off shiny surfaces.

b) State the relationship between the angle of incidence and the angle of reflection. [1] The angle of incidence is equal to the angle of reflection.

c) If the mirror is replaced with a piece of white paper, what will be observed on the screen? Explain. [1] No bright patch of light will be seen on the screen / The light will be scattered. White paper has a rough surface, so it reflects light in many directions (diffuse reflection) instead of one direction (regular reflection).

Question 34 (4 marks)

a) Complete the flowchart below to show the changes in state of water. [2]

Water (liquid) --(loses heat)--> Ice (solid)
Water (liquid) --(gains heat)--> Water vapour (gas)
Water vapour (gas) --(loses heat)--> Water (liquid)
Ice (solid) --(gains heat)--> Water (liquid)

b) Puddles of water on the ground dry up after rain even though the temperature is below the boiling point of water. Explain why. [2] Water evaporates at any temperature. Water molecules at the surface gain enough heat energy from the surroundings to escape as water vapour. This process (evaporation) occurs below boiling point.

Question 35 (3 marks)

Four materials A, B, C, D were tested for strength. Weights were added until each material broke. The results are shown.

a) Which material is the strongest? [1] Material C

b) A manufacturer wants to make a safety helmet. Which material (A, B, C, or D) is most suitable? Give a reason. [1] Material C. It is the strongest (withstands the most weight), providing the best protection.

c) State one other property the material for a safety helmet should have, besides strength. [1] Lightweight / Not too heavy / Comfortable / Durable / Waterproof / Heat resistant.

Question 36 (3 marks)

The diagram below shows the life cycle of a mosquito.

Image pending generation: diagram for Q36.

a) At which stage(s) does the mosquito live in water? [1] Egg, Larva, and Pupa stages (all except Adult).

b) The larva and pupa breathe through a breathing tube at the water surface. Why must they come to the water surface to breathe? [1] They need oxygen from the air / They do not have gills to breathe underwater / They breathe atmospheric air.

c) State one way to prevent mosquitoes from breeding in stagnant water. [1] Add oil to the water surface (suffocates larvae/pupae) / Cover water containers / Remove stagnant water / Introduce fish that eat larvae / Use larvicide.

Question 37 (4 marks)

a) The diagram below shows a plant cell and an animal cell.

Image pending generation: diagram for Q37.

Name two structures found in the plant cell but not in the animal cell. [2]

1. Cell wall
2. Chloroplasts (or Large central vacuole)

b) State the function of the nucleus in a cell. [1] Controls all activities of the cell / Contains genetic material (DNA) / Controls cell division.

c) Why do root cells of a plant not have chloroplasts? [1] Roots are underground and do not receive light, so they cannot photosynthesise / do not need to trap light energy.

Question 38 (4 marks)

a) The diagram shows a circuit with two bulbs, a battery, and a switch.

Image pending generation: diagram for Q38.

(i) What type of circuit is this? [1] Series circuit

(ii) When the switch is closed, both bulbs light up. If Bulb 1 fuses (blows), what happens to Bulb 2? Explain. [2] Bulb 2 will not light up / goes out. In a series circuit, there is only one path for current. If one bulb fuses, the circuit is broken/open, so current cannot flow to Bulb 2.

b) Draw a circuit diagram where two bulbs are connected such that if one bulb fuses, the other remains lit. [1] (Draw a parallel circuit: Battery → Switch → junction → Bulb 1 and Bulb 2 on separate branches → rejoin → Battery)

Question 39 (4 marks)

a) The graph below shows the temperature of water in a beaker as it is heated over time.

Image pending generation: graph for Q39.

(i) What is happening at the horizontal part of the graph (constant temperature)? [1] The water is boiling / changing state from liquid to gas.

(ii) Explain why the temperature remains constant during this period. [1] Heat energy is used to overcome forces of attraction between water molecules (latent heat) for the change of state, not to increase kinetic energy/temperature.

b) When the water vapour rises and touches a cooler lid, it forms water droplets. Name this process. [1] Condensation

c) State one difference between boiling and evaporation. [1] Boiling occurs at a fixed temperature (100°C) throughout the liquid; evaporation occurs at any temperature, only at the surface. / Boiling is rapid with bubbles; evaporation is slow. / Boiling needs continuous heat source; evaporation uses surrounding heat.

Question 40 (5 marks)

a) The diagram below shows a food chain.

Image pending generation: diagram for Q40.

(i) Which organism is the producer? [1] Grass

(ii) How many food chains are in this food web? [1] One (this is a single food chain, not a web). / If interpreted as food web: The diagram shows a food chain, not a web.

(iii) If all the frogs are removed, what will happen to the grass population? Explain. [2] The grass population will increase. Frogs eat grasshoppers. Without frogs, grasshopper population increases → more grasshoppers eat grass → grass population decreases. Wait: If frogs removed → grasshoppers increase → grass decreases. Let me re-read: "what will happen to the grass population?" If frogs (predators of grasshoppers) are removed → grasshoppers increase → more grass eaten → grass population decreases.

Correction: Grass population will decrease. Frogs eat grasshoppers. No frogs → more grasshoppers → more grass eaten → grass decreases.

b) The diagram below shows a pyramid of numbers for the food chain above.

Image pending generation: diagram for Q40.

Explain why the pyramid of numbers has this shape. [1] Energy is lost at each trophic level (as heat, waste, movement), so fewer organisms can be supported at higher levels. / Producers are most numerous to support the consumers above.

MARKING SCHEME SUMMARY

End of Answer Key