Primary 5 Science Practice Paper 2

TuitionGoWhere Practice Paper — Science Primary 5

Answer Key — Version 2 of 5

Topic Focus: Diversity Total Marks: 40

Section A: Multiple Choice Questions (10 marks)

1. B — The variety of living things in an environment [1]

• Marking note: "Biodiversity" refers to the range of different species, not just animals or humans.

2. B — The natural home or environment of an organism [1]

• Marking note: A habitat includes all the conditions an organism needs, not just food or movement.

3. B — A layer of fat under its skin [1]

• Marking note: The fat layer (blubber) insulates the polar bear against extreme cold. Thin fur, bright feathers, and large ears would increase heat loss.

4. C — Grass [1]

• Marking note: Producers make their own food through photosynthesis. Grass is the only producer in this food chain.

5. C — By photosynthesis [1]

• Marking note: Photosynthesis is a process of making food, not a method of seed dispersal. Wind, water, and animals are all valid dispersal methods.

6. B — Ensure the continuity of their kind [1]

• Marking note: Reproduction ensures that a species does not die out. It is not directly about growth, food, or movement.

7. C — Whale [1]

• Marking note: Whales breathe air through lungs, give birth to live young, and produce milk — all mammalian traits. Lizards, frogs, and crocodiles are not mammals.

8. B — Many interconnected food chains [1]

• Marking note: A food web shows the complex feeding relationships in an ecosystem, not just a single chain.

9. B — Deep roots to reach underground water [1]

• Marking note: Desert plants need to conserve water and access water deep underground. Broad leaves and thin stems would cause water loss.

10. C — Fish [1]

• Marking note: Following the key: Organism Y does not have feathers (not a bird), and has scales and gills → Fish.

Section B: Short Answer Questions (20 marks)

11. [2]

(a) Cold temperature / Ice / Snow / Low temperature / Strong winds [1]

• Accept any reasonable abiotic factor common to the Arctic.

(b) Thick, waxy stem to store water / Deep roots to reach underground water / Leaves reduced to spines to reduce water loss / Thick cuticle to prevent water evaporation [1]

• Accept any valid desert adaptation of a cactus.

12. [3]

(a) Small fish [1]

• Explanation: Algae = producer; Shrimp = primary consumer; Small fish = secondary consumer; Large fish = tertiary consumer; Eagle = quaternar consumer.*

(b) The population of shrimp would increase [1] because there would be no small fish to prey on them / feed on them [1].

• Marking note: Award 1 mark for stating "increase" and 1 mark for a valid reason. If the student says "decrease" but gives a valid reason for that (e.g., "because the ecosystem would be disrupted"), award 0 — the direct ecological effect is an increase.*

13. [3]

(a) Anther [1]

• Marking note: The anther is the part of the stamen that produces pollen.*

(b) Any two of the following: [2 — 1 mark each]

• Water / Moisture
• Suitable (warm) temperature
• Air / Oxygen
• Note: Light is not always required for germination (some seeds germinate in darkness). Accept it but do not penalise if not mentioned. Do NOT accept "soil" as a primary condition — seeds can germinate without soil.

14. [2]

• Marking note: Award 1 mark for each correctly completed column (all entries correct). Deduct 0.5 per column if one organism is misplaced. Maximum 2 marks.*

15. [2]

Any two of the following reasons: [1 mark each]

1. It reduces competition for resources (light, water, nutrients, space) between the parent plant and the seedlings.
2. It allows the species to spread to new habitats / colonise new areas.
3. It reduces the risk of all seeds being destroyed by disease, pests, or natural disasters in one location.

• Accept any two valid reasons.

16. [1]

Worm [1]

• Explanation: Following the key: No legs → go to "No legs?" branch. No shell → Worm.*

17. [2]

Accept any two valid differences. Sample answer: [1 mark each for any two correct differences]

• Marking note: Award 1 mark per valid difference. The difference must be a genuine contrast, not just a restatement.*

18. [3]

(a) Mushroom [1]

• Explanation: Mushrooms are fungi that break down dead organic matter, acting as decomposers.*

(b) Any valid 3-organism food chain from the list, e.g.: [2]

Grass → Butterfly → Bird [2] or Grass → Ant → Bird [2] or Grass → Earthworm → Bird [2]

• Marking note: Award 2 marks for a correct food chain with producer first and correct feeding relationship. Award 1 mark if the chain has only one error (e.g., wrong order or an invalid link). Award 0 if the chain is entirely incorrect or includes mushroom as a consumer.*

Section C: Structured / Longer Response Questions (10 marks)

19. [6]

(a) Any three of the following: [3 — 1 mark each]

• Water / Shallow sea water / Tidal water
• Mud / Mudflat / Waterlogged soil
• Tree canopy / Branches of mangrove trees
• Roots / Pneumatophores area
• Air above the water surface
• Accept any three distinct habitats within a mangrove ecosystem.

(b) The soil in a mangrove area is waterlogged and contains very little oxygen [1]. The breathing roots (pneumatophores) grow above the water/soil surface so that the mangrove tree can take in air/oxygen for respiration [1].

• Marking note: Award 1 mark for identifying the problem (waterlogged/low-oxygen soil) and 1 mark for explaining how pneumatophores solve the problem.*

(c) Any one of the following: [1]

• Mangroves provide food and shelter for many different species / a wide variety of organisms.
• They serve as breeding grounds / nurseries for many fish and crustaceans.
• They support a large number of different habitats within a small area.
• Accept any valid reason linking mangroves to high biodiversity.

20. [6]

(a) Any two of the following: [2 — 1 mark each]

• Use of pesticides / insecticides that kill bees
• Loss of flowering plants / habitat destruction
• Disease or parasites affecting bees
• Climate change / extreme weather conditions
• Pollution
• Accept any two plausible reasons.

(b) Bees are important pollinators [1]. Without bees, the flowers of the fruit trees would not be pollinated / would not be fertilised, so fewer fruits would be produced / fruit yield would decrease [1].

• Marking note: Award 1 mark for identifying bees as pollinators and 1 mark for linking reduced pollination to reduced fruit production.*

(c) Any two of the following: [2 — 1 mark each]

• Plant more flowering plants / wildflowers to provide food for bees
• Reduce or stop using pesticides / use bee-friendly pesticides
• Set up beehives / provide nesting sites for bees
• Create a bee-friendly garden with a variety of flowers that bloom at different times
• Accept any two practical and relevant actions.