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Primary 6 PSLE Science Semestral Assessment 2 (End of Year) Paper 5
Free P6 PSLE Science SA2 Paper 5, Nemo3 Exam version, with questions, answers, and PSLE-focused practice for Singapore students.
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TuitionGoWhere Practice Paper - Science Primary 6 PSLE (SA2 Version 5) - Answer Key
Total Marks: 100
SECTION A (56 marks)
1. Answer: (1) The oak tree obtains energy directly from the Sun.
Explanation: Producers (plants) make their own food through photosynthesis using sunlight. The oak tree is a producer. Grasshoppers are herbivores (prey only, not predators). Snakes eat multiple animals (frogs, mice). Mushrooms are decomposers (fungi), not producers. Marks: 2
2. Answer: (4) Whale – Fish
Explanation: Whales are mammals (they have hair, breathe with lungs, give live birth, feed young with milk), not fish. Moss and ferns are correctly classified as non-flowering plants. Bats are mammals. Marks: 2
3. Answer: (2) Nucleus
Explanation: The nucleus contains genetic material (DNA) and controls all cellular activities. The cell wall provides support, chloroplasts conduct photosynthesis, and the vacuole stores substances. Marks: 2
4. Answer: (2) Bala and Cindy
Explanation: Bala is correct – yeast is a fungus (microorganism) used in bread-making for fermentation. Cindy is correct – bacteria are microscopic and require a microscope to be seen. Ali is incorrect – many microorganisms are beneficial (e.g., gut bacteria, decomposers). Devi is incorrect – mould is a fungus, not bacteria. Marks: 2
5. Answer: (3) Pupa
Explanation: The pupa is a non-feeding, transformational stage. Eggs don't feed. Larvae feed actively. Adult mosquitoes feed on nectar (males) or blood (females). Marks: 2
6. Answer: (3) Y
Explanation: Mammals feed their young with milk. Only organism Y has "Feeds young with milk = Yes". W is a bird (feathers, lays eggs). X could be reptile/amphibian/fish. Z could be bird/insect (wings, lays eggs, no feathers). Marks: 2
7. Answer: (1) Algae population increases; Small fish population decreases
Explanation: Water fleas eat algae (primary consumers). Without water fleas, algae population increases (less predation). Small fish eat water fleas, so their food source disappears → population decreases. Marks: 2
8. Answer: (1) Cell → Tissue → Organ → Organ system → Organism
Explanation: This is the correct hierarchical organisation: cells form tissues, tissues form organs, organs form organ systems, organ systems form an organism. Marks: 2
9. Answer: (3) Alveoli
Explanation: Gaseous exchange (oxygen and carbon dioxide) occurs in the alveoli (air sacs) where capillaries are in close contact. The trachea, bronchi, and bronchioles are air passages only. Marks: 2
10. Answer: (3) Reptile
Explanation: Backbone = vertebrate. Lays eggs + dry scaly skin = reptile. Birds have feathers. Mammals have hair/fur. Amphibians have moist skin. Marks: 2
11. Answer: (2) Only the plant cell has chloroplasts.
Explanation: Plant cells have chloroplasts for photosynthesis; animal cells do not. Plant cells have cell walls; animal cells do not. Both have nuclei. Plant cells have large central vacuoles; animal cells have small vacuoles. Marks: 2
12. Answer: (1) A only
Explanation: At 30°C (room temperature), substances with boiling points below 30°C are gases. Only A (-196°C) is below 30°C. B (78°C), C (100°C), D (357°C) are liquids at 30°C. Marks: 2
13. Answer: (2) Condensation
Explanation: Condensation is the change of state from gas (water vapour) to liquid (water droplets). Evaporation is liquid to gas. Precipitation is liquid/solid falling. Transpiration is water vapour release from plants. Marks: 2
14. Answer: (1) A only
Explanation: Seeds need water, air, and suitable temperature (warmth) to germinate. A: has all three. B: no water. C: too cold (freezer). D: no air (oil layer prevents air). Marks: 2
15. Answer: (1) The steel paper clip becomes a temporary magnet with opposite polarity at the near end.
Explanation: Magnetic induction – the magnet induces temporary magnetism in the steel clip. The near end becomes an opposite pole (attraction), the far end becomes the same pole. Marks: 2
16. Answer: (2) The bulb becomes dimmer.
Explanation: Adding a bulb in series increases total resistance. Current decreases (I = V/R). Both bulbs share the voltage, so each gets less voltage → dimmer. Marks: 2
17. Answer: (2) 10 N
Explanation: Principle of moments: Load × Load arm = Effort × Effort arm. 20 N × 0.5 m = Effort × 1.0 m. Effort = 10 N. Marks: 2
18. Answer: (1) Light travels in straight lines.
Explanation: Sharp shadows form because light travels in straight lines and is blocked by opaque objects. Reflection and refraction involve bending/changing direction. Marks: 2
19. Answer: (3) R
Explanation: Density = Mass/Volume. P: 50/25 = 2 g/cm³. Q: 80/40 = 2 g/cm³. R: 120/30 = 4 g/cm³. S: 60/60 = 1 g/cm³. R has the greatest density. Marks: 2
20. Answer:
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TuitionGoWhere Practice Paper - Science Primary 6 PSLE (Answer Key)
Subject: Science
Level: Primary 6 PSLE
Paper: SA2 (Version 5)
Total Marks: 100
SECTION A (56 marks)
| Question | Answer | Explanation |
|---|---|---|
| 1 | (1) | The oak tree is a producer and obtains energy directly from the Sun through photosynthesis. The grasshopper is a primary consumer (prey) but not a predator. The snake has multiple food sources (frog, mouse). Mushrooms are decomposers, not producers. |
| 2 | (4) | Whales are mammals, not fish. They have hair, breathe air, give birth to live young, and feed young with milk. Moss and ferns are correctly classified as non-flowering plants. Bats are correctly classified as mammals. |
| 3 | (2) | The nucleus contains genetic material (DNA) and controls all cellular activities. The cell wall provides structural support, chloroplasts conduct photosynthesis, and vacuoles store substances. |
| 4 | (2) | Bala is correct: yeast is a fungus used in bread-making. Cindy is correct: bacteria are microscopic. Ali is incorrect: not all microorganisms are harmful (many are beneficial). Devi is incorrect: mould is a fungus, not bacteria. |
| 5 | (3) | The pupa stage is a non-feeding, transformational stage. Eggs don't feed, larvae feed actively, and adults feed on nectar/blood. |
| 6 | (3) | Organism Y has no wings, doesn't lay eggs, has no feathers, but feeds young with milk – characteristic of mammals. W is a bird, X could be a reptile/amphibian/fish, Z could be an insect/bird. |
| 7 | (1) | Without water fleas (primary consumers), algae (producers) have no consumers → population increases. Small fish (secondary consumers) lose their food source → population decreases. |
| 8 | (1) | Correct hierarchy: Cell → Tissue → Organ → Organ System → Organism. |
| 9 | (3) | Gaseous exchange (oxygen and carbon dioxide) occurs in the alveoli, which have thin walls and rich blood supply. |
| 10 | (3) | Backbone + lays eggs + dry scaly skin = Reptile. Birds have feathers. Amphibians have moist skin. Mammals have hair/fur and mostly give live birth. |
| 11 | (2) | Only plant cells have chloroplasts (for photosynthesis). Animal cells lack cell walls and large central vacuoles. Both have nuclei. |
| 12 | (1) | At 30°C, only substance A (boiling point -196°C) is a gas. B (78°C), C (100°C), D (357°C) are liquids at room temperature. |
| 13 | (2) | Condensation is the change from gas (water vapour) to liquid (water droplets). Evaporation is liquid to gas. Precipitation is liquid/solid falling. Transpiration is plant water loss as vapour. |
| 14 | (1) | Seeds need water, air, and suitable temperature (warmth). Only Set-up A has all three: wet cotton wool (water), room temperature (warmth), and air present. |
| 15 | (1) | Magnetic induction: the steel paper clip becomes a temporary magnet with opposite polarity at the near end, causing attraction. |
| 16 | (2) | Adding a bulb in series increases total resistance, reducing current. Both bulbs share the voltage, so each becomes dimmer. |
| 17 | (2) | Principle of moments: Effort × Effort arm = Load × Load arm. Effort × 1.0 = 20 × 0.5 → Effort = 10 N. |
| 18 | (1) | Light travels in straight lines (rectilinear propagation), which explains sharp shadow formation. |
| 19 | (3) | Density = Mass/Volume. P: 2.0 g/cm³, Q: 2.0 g/cm³, R: 4.0 g/cm³, S: 1.0 g/cm³. R has the greatest density. |
| 20 | (1) | Phototropism is growth response to light. Geotropism = gravity, Hydrotropism = water, Thigmotropism = touch. |
| 21 | (4) | Transporting oxygen is a function of the circulatory system (blood), not the skeletal system. |
| 22 | (1) | The ovary develops into the fruit after fertilisation. The ovule develops into the seed. |
| 23 | (2) | The small intestine has villi and microvilli for maximum surface area, where most nutrient absorption occurs. |
| 24 | (4) | Group D: moist skin, lay eggs in water, cold-blooded = amphibians (frog, toad). A = reptiles, B = birds, C = mammals. |
| 25 | (3) | [Question truncated in source - answer based on typical PSLE question] The process shown is photosynthesis. |
| 26 | (2) | [Question truncated] Typically: Heat travels from hot to cold regions. |
| 27 | (4) | [Question truncated] Typically: The object is a magnetic material (iron/steel). |
| 28 | (1) | [Question truncated] Typically: The water gains heat and evaporates. |
SECTION B (44 marks)
Question 29 (2 marks)
a) The cell membrane controls the movement of substances in and out of the cell.
b) The chloroplast contains chlorophyll to trap light energy for photosynthesis.
Question 30 (2 marks)
a) Organism A: Insect (3 body parts, 6 legs, 2 antennae, wings)
b) Organism B: Arachnid (2 body parts, 8 legs, no antennae, no wings)
Question 31 (3 marks)
a) The population of rabbits will increase because there are fewer hawks to prey on them.
b) The population of grass will decrease because more rabbits will eat the grass.
c) The population of foxes may increase initially due to more rabbits (food), but may later decrease if rabbits are over-hunted.
Question 32 (2 marks)
a) Process X: Evaporation
b) Process Y: Condensation
Question 33 (2 marks)
a) The bulb in Set-up A lights up because the circuit is closed/conductors allow electricity to flow.
b) The bulb in Set-up B does not light up because plastic is an insulator/open circuit.
Question 34 (3 marks)
a) The water in the beaker gains heat from the flame and expands (increases in volume).
b) The water level in the glass tube rises because the expanded water occupies more space.
c) When the flame is removed, the water loses heat to the surroundings, contracts, and the water level falls.
Question 35 (2 marks)
a) Force F: Friction / Frictional force
b) The frictional force opposes the motion, causing the toy car to slow down and stop.
Question 36 (3 marks)
a) The shadow is formed because the cardboard is opaque and blocks light.
b) The shadow becomes larger when the torch is moved closer to the cardboard.
c) The shadow becomes smaller when the screen is moved closer to the cardboard.
Question 37 (2 marks)
a) Material X: Metal (e.g., copper/aluminium) – good conductor of heat
b) Material Y: Plastic/Wood – poor conductor of heat (insulator)
Question 38 (3 marks)
a) The stomach produces gastric juice containing enzymes to digest proteins.
b) The small intestine completes digestion and absorbs digested food into the bloodstream.
c) The large intestine absorbs water from undigested food.
Question 39 (2 marks)
a) The plant responds to gravity (geotropism) – roots grow downwards, shoots grow upwards.
b) This ensures roots anchor the plant and absorb water/minerals, while shoots reach sunlight for photosynthesis.
Question 40 (4 marks)
a) The magnet attracts the steel pins because steel is a magnetic material.
b) When the switch is opened, the electromagnet loses its magnetism and the pins fall off.
c) Increase the number of coils around the iron core / Increase the number of batteries / Use a thicker iron core.
d) Electromagnets can be turned on/off and their strength can be controlled, unlike permanent magnets.
Question 41 (3 marks)
a) The volume of the stone is 20 cm³ (50 cm³ - 30 cm³).
b) Density = Mass/Volume = 60 g / 20 cm³ = 3 g/cm³.
c) The stone sinks because its density (3 g/cm³) is greater than water's density (1 g/cm³).
Question 42 (4 marks)
a) The chest cavity expands (ribs move up and out, diaphragm moves down).
b) Air pressure in the lungs decreases below atmospheric pressure.
c) Air rushes in from outside (higher pressure) to the lungs (lower pressure).
d) During exhalation, the chest cavity decreases in volume, air pressure in lungs increases, and air is pushed out.
Question 43 (3 marks)
a) The green pigment in leaves is called chlorophyll.
b) Chlorophyll traps light energy to convert carbon dioxide and water into food (glucose) and oxygen.
c) Without light, photosynthesis cannot occur, so the plant cannot make food and will eventually die.
Question 44 (4 marks)
a) The water in the wet towel gains heat from the body and evaporates.
b) Evaporation takes away heat from the body, lowering body temperature.
c) On a windy day, evaporation occurs faster, cooling the body more quickly.
d) On a humid day, evaporation is slower because the air already contains much water vapour, reducing cooling effect.
MARKING SCHEME SUMMARY
| Section | Questions | Marks per Question | Total Marks |
|---|---|---|---|
| A | 1-28 | 2 | 56 |
| B | 29-44 | 2-4 | 44 |
| Total | 100 |
GRADING GUIDELINES (PSLE Standard)
| Score Range | Achievement Level (AL) | Description |
|---|---|---|
| 90-100 | AL1 | Excellent understanding |
| 85-89 | AL2 | Very good understanding |
| 80-84 | AL3 | Good understanding |
| 75-79 | AL4 | Satisfactory understanding |
| 65-74 | AL5 | Adequate understanding |
| 45-64 | AL6 | Basic understanding |
| 20-44 | AL7 | Limited understanding |
| <20 | AL8 | Very limited understanding |
End of Answer Key