Primary 5 Science Semestral Assessment 1 (Mid-Year) Paper 1

TuitionGoWhere Practice Paper - Science Primary 5 (Answer Key)

Topic Focus: Diversity (Adaptations, Classification, Interactions)

Section A (28 marks)

1. (3)

• Reasoning: Mammals are characterized by having hair or fur and giving birth to live young. Animal C fits this description. Animal A is a reptile, B is a bird, and D is an amphibian.

2. (2)

• Reasoning: Group Y consists of organisms without chlorophyll. Group Q has more than 6 legs.
  • Ant (6 legs) -> Group P.
  • Spider (8 legs) -> Group Q.
  • Butterfly (6 legs) -> Group P.
  • Beetle (6 legs) -> Group P.
  • Therefore, the Spider belongs to Group Q.

3. (2)

• Reasoning: In a hot and dry desert, water conservation is critical. A thick waxy skin (cuticle) reduces water loss through evaporation. Broad leaves (1) would increase water loss. Shallow roots (3) are for absorbing surface rain, but the waxy skin is the primary adaptation for retaining water in the heat. Green stems (4) are for photosynthesis since leaves are reduced, but the waxy skin is the direct adaptation to the dryness.

4. (2)

• Reasoning: Ladybirds eat aphids. If ladybirds decrease, there are fewer predators to eat the aphids. Therefore, the aphid population will increase. This may eventually lead to a decrease in plants, but the immediate effect is on the aphids.

5. (3)

• Reasoning: Fungi are not plants; they do not have chlorophyll and cannot make their own food (photosynthesis). They are saprophytes, meaning they obtain nutrients by breaking down dead and decaying organic matter.

6. (1)

• Reasoning: White fur provides camouflage against the snow (hiding from prey/predators). The thick layer of fat (blubber) acts as insulation to keep the bear warm in freezing temperatures.

7. (2)

• Reasoning: Part B is the Anther, which is part of the stamen (male reproductive organ). The anther produces pollen. Part A is the Stigma (receives pollen), C is the Petal (attracts pollinators), and D is the Ovary (contains ovules).

8. (2)

• Reasoning: All insects have three main body parts: head, thorax, and abdomen. Not all insects have wings (e.g., silverfish), not all live on land (e.g., water striders), and while many undergo metamorphosis, the defining structural characteristic is the 3 body parts and 6 legs.

9. (2)

• Reasoning: Trace the paths from producer to top consumer:
  1. Grass → Rabbit → Fox
  2. Grass → Grasshopper → Frog → Snake → Eagle There are only 2 distinct chains shown in the description provided in the placeholder. Note: If the diagram implied Rabbit also eaten by Eagle, it would be 3, but based on standard simple webs described: Grass->Rabbit->Fox and Grass->Grasshopper->Frog->Snake->Eagle. Correction based on typical exam patterns: Let's re-read the placeholder description carefully: "Grass is eaten by Rabbit and Grasshopper. Rabbit is eaten by Fox. Grasshopper is eaten by Frog. Frog is eaten by Snake. Snake is eaten by Eagle." Chain 1: Grass → Rabbit → Fox Chain 2: Grass → Grasshopper → Frog → Snake → Eagle Total = 2 chains. Answer is (1). Wait, looking at options: (1) 2, (2) 3, (3) 4, (4) 5. Let's check if I missed a link. Usually, these webs are slightly more complex. If the Fox also eats the Frog? No, not stated. If the Eagle eats the Rabbit? Not stated. Based strictly on the text description in the placeholder: 2 chains. Self-Correction: Often in these questions, there might be a cross-link. However, without explicit cross-links in the text description, we stick to 2. Alternative interpretation: Did the prompt imply a standard web? "Grass -> Rabbit -> Fox" and "Grass -> Grasshopper -> Frog -> Snake -> Eagle". That is 2. Let's assume the question implies a slightly richer web often seen in exams where Fox might also eat Frog? No, stick to the text. Actually, let's look at Q9 options again. If the answer is 2, option (1) is correct.

10. (3)

• Reasoning: Decomposers (bacteria and fungi) break down dead plants and animals. This process releases nutrients (minerals) back into the soil, which are then absorbed by plants for growth.

11. (4)

• Reasoning: Grasshoppers are insects. Insects breathe through tiny openings called spiracles and a system of tubes called tracheae. They do not have lungs. Fish use gills, humans use lungs, and earthworms use moist skin.

12. (2)

• Reasoning: Animals with jointed legs, a hard outer shell (exoskeleton), and no backbone are Arthropods. This group includes insects, arachnids, and crustaceans.

13. (2)

• Reasoning: Hibernation is an action or behavior that an animal performs to survive cold winters. Changing skin color (1) is physiological/structural. Spines (3) and webbed feet (4) are structural physical features.

14. (2)

• Reasoning: Interdependence refers to the reliance of different organisms on each other for survival. The trees provide shelter, and the birds protect the trees from pests. They depend on each other.

Section B (28 marks)

15. (a) Plant P. [1] Explanation: Rainforests are wet and have plenty of sunlight. Broad and flat leaves allow the plant to trap maximum sunlight for photosynthesis in the shaded undergrowth, and the soft stem suggests it does not need to support heavy weight against strong winds or dryness. [1] (Note: Accept "Broad leaves trap more sunlight" as the key reason.)

(b) The shallow and widespread roots allow the cactus to absorb water quickly from a large area of the soil surface when it rains briefly in the desert. [2] (1 mark for "absorb water quickly", 1 mark for "large surface area/widespread".)

16. (a) Mammal [1]

(b) Because it gives birth to young ones (and has hair), whereas birds lay eggs and have feathers. [1] (Key distinction: Reproduction method and body covering.)

(c) Arachnid [1]

17. (a) The prop roots provide support and stability for the tree in the soft, muddy soil, preventing it from toppling over. [2] (1 mark for "support/stability", 1 mark for "soft/muddy soil".)

(b) Structural adaptation [1] (It is a physical feature of the plant's body.)

18. (a) Plant B did not receive sunlight, so it could not produce chlorophyll (or the chlorophyll broke down). Without chlorophyll, it cannot make food and turns yellow. [2] (1 mark for "no sunlight/chlorophyll", 1 mark for "cannot make food/yellowing".)

(b) Photosynthesis [1]

(c) Carbon dioxide and Water [2] (1 mark each. Order does not matter.)

19. (a) The soil it grows in is poor in nutrients (specifically nitrogen). It traps insects to obtain these missing nutrients for growth. [2] (1 mark for "soil poor in nutrients", 1 mark for "obtain nutrients/nitrogen".)

(b) Structural adaptations. [1] Explanation: The sweet smell is produced by glands (physical structure/chemical) and the slippery rim is a physical feature of the leaf. They are not actions the plant chooses to do at a specific time like migration. [1] (Note: At Primary level, scent is often debated, but "slippery rim" is definitely structural. If the student argues behavioral, it is incorrect because plants do not have "behavior" in the animal sense. Stick to Structural.)

20. (a) The base represents the producers (plants). There are the most producers because they capture energy from the sun to support all other levels. They have the highest biomass/energy. [2] (1 mark for "producers/plants", 1 mark for "most energy/biomass to support others".)

(b) The population of tertiary consumers will decrease. [1] Explanation: If producers die, primary consumers have no food and die. This causes a shortage of food for secondary consumers, and finally for tertiary consumers. The energy flow is cut off. [1] (1 mark for "decrease", 1 mark for "chain reaction/loss of food source".)

(c) Energy is lost as heat during respiration / Energy is used for movement and life processes / Some parts of the organism are not eaten or digested (waste). [1] (Any one valid reason.)