From Real Exams Exam Paper
Primary 6 PSLE Science Semestral Assessment 2 (End of Year) Paper 2
Free P6 PSLE Science SA2 Paper 2, Nemo3 Exam version, with questions, answers, and PSLE-focused practice for Singapore students.
These static practice materials are generated from the site's syllabus and paper-generation workflow, with source and model context shown so students and parents can evaluate the material before use.
Questions
TuitionGoWhere Practice Paper - Science Primary 6 PSLE
TuitionGoWhere Exam Practice (AI)
Subject: Science
Level: Primary 6 PSLE
Paper: SA2 Version 2
Duration: 1 h 45 min
Total Marks: 100
Name: ________________________
Class: Primary 6 ______
Date: ________________________
INSTRUCTIONS TO CANDIDATES
- Do not open this booklet until you are told to do so.
- Follow all instructions carefully.
- Answer all questions.
- For Section A, shade your answers on the Optical Answer Sheet (OAS) provided.
- For Section B, write your answers in the spaces provided in this booklet.
- The number of marks is given in brackets [ ] at the end of each question or part question.
- The total marks for this paper is 100.
SECTION A (56 marks)
For each question from 1 to 28, four options are given. One of them is the correct answer. Make your choice (1, 2, 3 or 4) and shade the correct oval on the Optical Answer Sheet.
Each question carries 2 marks.
Question 1
Which of the following statements about living things is incorrect?
(1) All living things need air, food and water to survive.
(2) All living things can reproduce.
(3) All living things respond to changes around them.
(4) All living things can make their own food.
Question 2
Study the classification chart below.
Generated diagram for Q2.
Which group of organisms is classified incorrectly in the chart?
(1) Mushroom → Non-flowering plants
(2) Bat → Mammals
(3) Penguin → Birds
(4) Whale → Fish
Question 3
The diagram below shows a cell.
Generated diagram for Q3.
Which of the following statements about the cell is correct?
(1) It is an animal cell because it has a nucleus.
(2) It is a plant cell because it has a cell wall and chloroplasts.
(3) It is a bacterial cell because it has a cell membrane.
(4) It is a fungal cell because it has a large vacuole.
Question 4
Four students made the following statements about microorganisms.
| Student | Statement |
|---|---|
| Ali | All microorganisms are harmful. |
| Bala | Yeast is a microorganism that can reproduce. |
| Cindy | Bacteria can only be seen with a microscope. |
| Devi | Mould is a type of bacteria. |
Which two students made correct statements?
(1) Ali and Bala
(2) Bala and Cindy
(3) Cindy and Devi
(4) Ali and Devi
Question 5
Study the flowchart below.
Generated diagram for Q5.
Organism X has a backbone, lays eggs, and has feathers. Organism Y has no backbone, has 8 legs, and 2 body parts.
Which of the following correctly identifies Organism X and Organism Y?
(1) X: Bird, Y: Insect
(2) X: Bird, Y: Arachnid
(3) X: Reptile, Y: Arachnid
(4) X: Mammal, Y: Insect
Question 6
Which of the following pairs of organisms are both decomposers?
(1) Earthworm and mushroom
(2) Bacteria and mushroom
(3) Yeast and earthworm
(4) Mould and fern
Question 7
The table below shows the characteristics of four organisms, P, Q, R and S. A tick (✓) indicates the presence of the characteristic.
| Characteristic | P | Q | R | S |
|---|---|---|---|---|
| Has cell wall | ✓ | ✓ | ✗ | ✗ |
| Has chloroplasts | ✓ | ✗ | ✗ | ✗ |
| Can move freely | ✗ | ✗ | ✓ | ✓ |
| Reproduces by spores | ✗ | ✓ | ✗ | ✗ |
Which organism is most likely a fungus?
(1) P
(2) Q
(3) R
(4) S
Question 8
Study the food web below.
Generated diagram for Q8.
How many food chains in the food web have exactly four organisms?
(1) 2
(2) 3
(3) 4
(4) 5
Question 9
Which of the following adaptations is structural?
(1) A bird migrating to a warmer country in winter.
(2) A chameleon changing its skin colour to match the surroundings.
(3) A cactus having thick, fleshy stems to store water.
(4) A bear hibernating during winter.
Question 10
The diagram below shows the life cycle of a mosquito.
Generated diagram for Q10.
At which stage(s) does the mosquito live in water?
(1) Egg only
(2) Larva and pupa only
(3) Egg, larva and pupa only
(4) All four stages
Question 11
Which of the following statements about bacteria is correct?
(1) All bacteria cause diseases.
(2) Bacteria reproduce by binary fission.
(3) Bacteria are multicellular organisms.
(4) Bacteria have a nucleus.
Question 12
Study the classification table below.
| Group | Example | Body Covering | Breathing Method | Reproduction |
|---|---|---|---|---|
| A | Frog | Moist skin | Lungs, skin, gills | Lay eggs in water |
| B | Snake | Dry scales | Lungs | Lay eggs on land |
| C | Penguin | Feathers | Lungs | Lay eggs on land |
| D | Whale | Hair | Lungs | Give birth to young |
Which group represents amphibians?
(1) A
(2) B
(3) C
(4) D
Question 13
The diagram below shows a fern plant.
Generated diagram for Q13.
How does the fern reproduce?
(1) By seeds from flowers
(2) By spores from the sori
(3) By budding from the rhizome
(4) By fragmentation of the roots
Question 14
Which of the following organisms is incorrectly matched to its group?
(1) Moss → Non-flowering plant
(2) Mushroom → Fungi
(3) Yeast → Bacteria
(4) Amoeba → Protozoa
Question 15
The diagram below shows a food chain.
Generated diagram for Q15.
If the population of caterpillars decreases drastically due to a disease, what will most likely happen to the plant and bird populations?
| Plant population | Bird population |
|---|---|
| (1) Increases | Increases |
| (2) Increases | Decreases |
| (3) Decreases | Increases |
| (4) Decreases | Decreases |
Question 16
Which of the following is not a characteristic of insects?
(1) Three body parts: head, thorax, abdomen
(2) Six legs
(3) Two pairs of wings
(4) Eight legs
Question 17
Study the diagram below showing the human digestive system.
Generated diagram for Q17.
In which organ does most absorption of digested food take place?
(1) Stomach
(2) Small intestine
(3) Large intestine
(4) Liver
Question 18
Which of the following shows the correct order of classification from broadest to most specific?
(1) Kingdom → Phylum → Class → Order → Family → Genus → Species
(2) Species → Genus → Family → Order → Class → Phylum → Kingdom
(3) Kingdom → Class → Phylum → Order → Family → Genus → Species
(4) Phylum → Kingdom → Class → Order → Family → Genus → Species
Question 19
The table below shows the characteristics of four unknown organisms.
| Organism | Nucleus | Cell Wall | Chloroplasts | Mode of Nutrition |
|---|---|---|---|---|
| W | Yes | Yes (cellulose) | Yes | Autotrophic |
| X | Yes | Yes (chitin) | No | Saprotrophic |
| Y | No | Yes (peptidoglycan) | No | Heterotrophic |
| Z | Yes | No | No | Heterotrophic |
Which organism is a plant?
(1) W
(2) X
(3) Y
(4) Z
Question 20
Which of the following statements about viruses is correct?
(1) Viruses are living things because they can reproduce.
(2) Viruses can only reproduce inside a living host cell.
(3) Viruses can be killed by antibiotics.
(4) Viruses are larger than bacteria.
Question 21
Study the food web below.
Generated diagram for Q21.
Which organism is both a predator and a prey?
(1) Phytoplankton
(2) Zooplankton
(3) Shark
(4) Turtle
Question 22
The diagram below shows a typical animal cell and a typical plant cell.
Generated diagram for Q22.
Which structure is present in the plant cell but absent in the animal cell?
(1) Nucleus
(2) Cell membrane
(3) Chloroplasts
(4) Cytoplasm
Question 23
Which of the following groups of organisms all reproduce by spores?
(1) Fern, moss, mushroom
(2) Fern, mushroom, yeast
(3) Moss, mushroom, bacteria
(4) Mushroom, yeast, mould
Question 24
The diagram below shows a fish and a dolphin.
Generated diagram for Q24.
Which statement correctly explains why a dolphin is not a fish?
(1) Dolphins live in water but fish live on land.
(2) Dolphins breathe with lungs but fish breathe with gills.
(3) Dolphins have fins but fish have flippers.
(4) Dolphins lay eggs but fish give birth to live young.
Question 25
Study the flowchart below.
Generated diagram for Q25.
Organism M has chlorophyll, cannot move freely, and has a cell wall made of cellulose. Which group does Organism M belong to?
(1) Euglena
(2) Plant
(3) Fungi
(4) Bacteria
Question 26
Which of the following is a behavioural adaptation?
(1) Polar bear having thick fur
(2) Camel having hump to store fat
(3) Birds flying in V-formation during migration
(4) Cactus having spines instead of leaves
Question 27
The diagram below shows a yeast cell budding.
Generated diagram for Q27.
What type of reproduction is this?
(1) Sexual reproduction
(2) Asexual reproduction
(3) Spore formation
(4) Binary fission
Question 28
Which of the following statements about classification is incorrect?
(1) Classification helps scientists organise living things into groups.
(2) Organisms in the same species can interbreed to produce fertile offspring.
(3) The more classification groups two organisms share, the more closely related they are.
(4) All organisms in the same genus have the same species name.
SECTION B (44 marks)
Write your answers in the spaces provided. The number of marks is given in brackets [ ] at the end of each question or part question.
Question 29
The diagram below shows a plant cell and an animal cell.
Generated diagram for Q29.
(a) Label the cell wall and chloroplasts in the plant cell diagram. [1]
(b) State two differences between the plant cell and the animal cell shown. [2]
Difference 1: _________________________________________________________________
Difference 2: _________________________________________________________________
(c) Explain why chloroplasts are important for the plant cell. [1]
Question 30
Study the classification chart below.
Generated diagram for Q30.
(a) State the main characteristic used to classify animals into vertebrates and invertebrates. [1]
(b) A student found an animal with the following characteristics:
- Has a backbone
- Has dry scales
- Breathes through lungs
- Lays eggs with leathery shells on land
(i) Which vertebrate group does this animal belong to? [1]
(ii) Give an example of an animal from this group. [1]
(c) State one difference between amphibians and reptiles in terms of their skin. [1]
Question 31
The diagram below shows a food web in a garden ecosystem.
Generated diagram for Q31.
(a) How many producers are there in this food web? [1]
(b) Write one food chain with four organisms from this food web. [1]
(c) The population of grasshoppers decreases due to a pesticide. Explain how this affects the frog population and the grass population. [2]
Frog population: _______________________________________________________________
Grass population: _______________________________________________________________
(d) State the role of decomposers in this ecosystem. [1]
Question 32
The table below shows the characteristics of five organisms.
| Organism | Cell Type | Nucleus | Cell Wall | Chloroplasts | Nutrition |
|---|---|---|---|---|---|
| A | Prokaryotic | No | Yes (peptidoglycan) | No | Heterotrophic |
| B | Eukaryotic | Yes | Yes (cellulose) | Yes | Autotrophic |
| C | Eukaryotic | Yes | Yes (chitin) | No | Saprotrophic |
| D | Eukaryotic | Yes | No | No | Heterotrophic |
| E | Eukaryotic | Yes | Yes (cellulose) | No | Autotrophic* |
*Organism E is a non-flowering plant that does not produce seeds.
(a) Which organism(s) is/are bacteria? [1]
(b) Which organism is a fungus? [1]
(c) Organism E is a fern. Explain how a fern reproduces without seeds. [2]
(d) State one similarity and one difference between Organism B (flowering plant) and Organism E (fern). [2]
Similarity: ___________________________________________________________________
Difference: ___________________________________________________________________
Question 33
The diagram below shows the life cycle of a butterfly.
Generated diagram for Q33.
(a) Name the type of metamorphosis shown by the butterfly. [1]
(b) State one difference between the larva and the adult butterfly in terms of feeding. [1]
(c) The caterpillar has strong mandibles (jaws). Explain how this adaptation helps the caterpillar survive. [1]
(d) The adult butterfly has brightly coloured wings. State one function of this adaptation. [1]
Question 34
Study the diagram below showing a mushroom growing on a rotting log.
Generated diagram for Q34.
(a) Name the reproductive structure of the mushroom that produces spores. [1]
(b) The mycelium grows into the rotting log. Explain why the mycelium does this. [1]
(c) State one difference between how mushrooms and yeast obtain food. [1]
(d) Mushrooms are decomposers. Explain why decomposers are important in an ecosystem. [2]
Question 35
The diagram below shows a fish and a frog (adult).
Generated diagram for Q35.
(a) State one similarity between the fish and the frog in terms of reproduction. [1]
(b) State two differences between the fish and the frog in terms of breathing and body covering. [2]
Difference 1 (Breathing): ________________________________________________________
Difference 2 (Body covering): ____________________________________________________
(c) The frog lays its eggs in water. Explain why this is necessary for the survival of the eggs. [1]
(d) Tadpoles have gills and tails. Adult frogs have lungs and legs. Explain how these changes help the frog survive in different environments during its life cycle. [2]
Question 36
The diagram below shows a food pyramid (pyramid of numbers) for a grassland ecosystem.
Generated diagram for Q36.
(a) Which organism is the producer? [1]
(b) Calculate the total number of consumers in this pyramid. [1]
(c) If a disease kills all the snakes, explain what will happen to the mouse population and the grasshopper population. [2]
Mouse population: _____________________________________________________________
Grasshopper population: _________________________________________________________
(d) Energy is lost at each trophic level. State two ways in which energy is lost. [2]
Question 37
Study the flowchart below used to classify five organisms: Moss, Fern, Mushroom, Bacteria, Yeast.
Generated diagram for Q37.
(a) Using the flowchart, state the group each organism belongs to. [2]
Moss: ________________________________________________________________________
Fern: _________________________________________________________________________
Mushroom: ____________________________________________________________________
Bacteria: ______________________________________________________________________
Yeast: ________________________________________________________________________
(b) State one difference between bacteria and yeast in terms of cell structure. [1]
(c) Moss and fern are both non-flowering plants. State one difference between them. [1]
Question 38
The diagram below shows a cell viewed under a microscope.
Image pending generation: diagram for Q38.
(a) Is this a plant cell or an animal cell? [1]
(b) Give two reasons for your answer in (a). [2]
Reason 1: _____________________________________________________________________
Reason 2: _____________________________________________________________________
(c) State the function of the cell wall. [1]
(d) The cell is placed in a concentrated salt solution. Describe what happens to the cell membrane and cytoplasm. [1]
Question 39
The table below shows the adaptations of four organisms living in different environments.
| Organism | Environment | Adaptation |
|---|---|---|
| Polar bear | Arctic | Thick fur, thick fat layer, white fur |
| Cactus | Desert | Spines, thick fleshy stem, shallow widespread roots |
| Camel | Desert | Hump (fat storage), long eyelashes, wide feet |
| Penguin | Antarctic | Feathers, blubber, huddling behaviour |
(a) Classify each adaptation as Structural (S) or Behavioural (B). [2]
| Adaptation | S or B |
|---|---|
| Thick fur (polar bear) | ______ |
| Huddling behaviour (penguin) | ______ |
| Spines (cactus) | ______ |
| Wide feet (camel) | ______ |
(b) Explain how the shallow widespread roots of the cactus help it survive in the desert. [1]
(c) The polar bear has white fur. State two functions of this adaptation. [2]
(d) Define the term adaptation. [1]
Question 40
The diagram below shows an experiment to investigate the conditions needed for mould growth on bread.
Generated experimental_setup for Q40.
(a) Which two setups should be compared to show that moisture is needed for mould growth? [1]
(b) In which setup(s) will mould most likely grow? [1]
(c) Explain why mould grows faster in warm conditions than in cold conditions. [1]
(d) State one way to prevent mould growth on food. [1]
END OF PAPER
Answers
TuitionGoWhere Practice Paper - Science Primary 6 PSLE (Answer Key)
Subject: Science
Level: Primary 6 PSLE
Paper: SA2 Version 2
Total Marks: 100
SECTION A (56 marks)
Question 1
Answer: (4)
Explanation: Not all living things can make their own food. Only plants (producers) can make their own food through photosynthesis. Animals and fungi are consumers/decomposers that obtain food by eating other organisms.
Key concept: Living things need air, food, water; can reproduce; respond to changes. Only plants are autotrophic.
Question 2
Answer: (4)
Explanation: Whales are mammals, not fish. They breathe with lungs, give birth to live young, feed young with milk, and have hair (though minimal). Mushrooms are fungi (not plants), but the chart classifies them under non-flowering plants which is a common simplification in primary science. Bats are mammals. Penguins are birds.
Key concept: Vertebrate classification - whales are marine mammals.
Question 3
Answer: (2)
Explanation: The cell has a cell wall and chloroplasts, which are characteristic of plant cells. Animal cells lack cell walls and chloroplasts. Bacterial cells are prokaryotic (no nucleus). Fungal cells have cell walls made of chitin, not cellulose, and lack chloroplasts.
Key concept: Plant cell identification - cell wall (cellulose) and chloroplasts are key distinguishing features.
Question 4
Answer: (2)
Explanation: Bala is correct - yeast is a microorganism (fungus) that reproduces by budding. Cindy is correct - bacteria are microscopic and require a microscope to be seen. Ali is incorrect - not all microorganisms are harmful (e.g., yeast in bread, bacteria in yogurt, decomposers). Devi is incorrect - mould is a fungus, not a bacterium.
Key concept: Microorganism classification and beneficial/harmful roles.
Question 5
Answer: (2)
Explanation: Organism X has a backbone (vertebrate), feathers → Bird. Organism Y has no backbone (invertebrate), 8 legs → Arachnid (spiders, scorpions). Insects have 6 legs.
Key concept: Using dichotomous keys/flowcharts for classification.
Question 6
Answer: (2)
Explanation: Bacteria and mushrooms (fungi) are both decomposers. Earthworms are detritivores (consume dead matter but are animals). Yeast is a fungus but is a microorganism, not typically classified as a decomposer in the same ecological role. Ferns are plants (producers).
**
<stage3_exam_answers_md>
TuitionGoWhere Practice Paper - Science Primary 6 PSLE (Answer Key)
Subject: Science
Level: Primary 6 PSLE
Paper: SA2 Version 2
SECTION A (56 marks)
| Question | Answer | Explanation |
|---|---|---|
| 1 | (4) | Not all living things can make their own food. Only plants (producers) can photosynthesise. Animals and fungi are consumers/decomposers. |
| 2 | (1) and (4) | Mushroom is a fungus, not a non-flowering plant. Whale is a mammal, not a fish. |
| 3 | (2) | The cell has a cell wall and chloroplasts, which are characteristic of plant cells. |
| 4 | (2) | Bala: Yeast is a microorganism that reproduces (by budding). Cindy: Bacteria are microscopic. Ali is wrong (some microorganisms are beneficial). Devi is wrong (mould is a fungus, not bacteria). |
| 5 | (2) | Organism X has backbone + feathers = Bird. Organism Y has no backbone + 8 legs + 2 body parts = Arachnid. |
| 6 | (2) | Bacteria and mushroom (fungi) are both decomposers. Earthworm is a detritivore, yeast is a fungus but often classified separately, mould is a fungus (decomposer) but fern is a plant. |
| 7 | (2) | Organism Q: Has cell wall, no chloroplasts, cannot move freely, reproduces by spores → Fungus. P is a plant, R and S are animals. |
| 8 | (3) | Food chains with exactly 4 organisms: Plant→Grasshopper→Frog→Snake; Plant→Grasshopper→Bird→Hawk; Plant→Caterpillar→Bird→Hawk; Plant→Rabbit→Snake→Hawk. (4 chains) |
| 9 | (3) | Structural adaptation: physical feature (thick fleshy stems). Others are behavioural adaptations. |
| 10 | (3) | Egg, larva, and pupa stages live in water. Adult is terrestrial/flying. |
| 11 | (2) | Bacteria reproduce asexually by binary fission. Not all cause diseases; they are unicellular; they lack a nucleus (prokaryotes). |
| 12 | (1) | Group A: Frog = amphibian (moist skin, breathes through lungs/skin/gills, lays eggs in water). |
| 13 | (2) | Ferns reproduce by spores produced in sori on the underside of fronds. |
| 14 | (3) | Yeast is a fungus, not a bacterium. |
| 15 | (2) | Fewer caterpillars → less eaten plants → plant population increases. Fewer caterpillars → less food for birds → bird population decreases. |
| 16 | (4) | Insects have six legs, not eight. Eight legs is characteristic of arachnids. |
| 17 | (2) | Small intestine is the main site for absorption of digested nutrients (villi increase surface area). |
| 18 | (1) | Correct taxonomic hierarchy: Kingdom → Phylum → Class → Order → Family → Genus → Species. |
| 19 | (1) | Organism W: Nucleus + cellulose cell wall + chloroplasts + autotrophic = Plant. X = Fungus (chitin), Y = Bacteria (peptidoglycan, no nucleus), Z = Animal (no cell wall). |
| 20 | (2) | Viruses are obligate intracellular parasites; they replicate only inside living host cells. They are non-living outside host; antibiotics don't work on them; they are smaller than bacteria. |
| 21 | (2) | Zooplankton eats phytoplankton (predator) and is eaten by small fish/jellyfish (prey). Phytoplankton is producer only; Shark and Turtle are top predators only. |
| 22 | (3) | Chloroplasts are present in plant cells (for photosynthesis) but absent in animal cells. |
| 23 | (1) | Fern (spores), moss (spores), mushroom (spores) all reproduce by spores. Yeast buds; bacteria binary fission; mould spores but yeast/bacteria not spores. |
| 24 | (2) | Dolphins are mammals: breathe air with lungs, give live birth, produce milk. Fish have gills, lay eggs (mostly). |
| 25 | (2) | Has chlorophyll → cannot move freely → Plant. (Euglena moves freely; fungi/bacteria/protozoa lack chlorophyll). |
| 26 | (3) | Behavioural adaptation: action/behaviour (flying in V-formation). Others are structural (fur, hump, spines). |
| 27 | (2) | Budding is a form of asexual reproduction (offspring genetically identical to parent). |
| 28 | (4) | Organisms in the same genus have the same genus name but different species names (e.g., Panthera leo, Panthera tigris). |
SECTION B (44 marks)
Question 29
(a) Structure A: Cell wall
Structure B: Chloroplasts
[2]
(b) Function of cell wall: Provides shape and support to the plant cell / Protects the cell / Prevents cell from bursting when water enters.
Function of chloroplasts: Contains chlorophyll to trap light energy for photosynthesis / Site of photosynthesis.
[2]
(c) The animal cell does not have a cell wall, so it cannot maintain a fixed shape and is irregular/round. The plant cell has a rigid cell wall giving it a fixed, rectangular shape.
[1]
Question 30
(a) Group X: Fungi
Group Y: Bacteria
[1]
(b) Fungi: Cell wall made of chitin (accept: reproduce by spores, saprotrophic nutrition, eukaryotic).
Bacteria: No nucleus / Prokaryotic / Cell wall made of peptidoglycan (accept: reproduce by binary fission, unicellular).
[2]
(c) Yeast is a fungus (unicellular fungus) but is microscopic like bacteria. It reproduces by budding (asexual), not binary fission. It has a nucleus (eukaryotic) and cell wall made of chitin, not peptidoglycan.
[2]
Question 31
(a) Food chain: Plant → Grasshopper → Frog → Snake → Hawk
(or Plant → Caterpillar → Bird → Hawk; Plant → Rabbit → Snake → Hawk, etc.)
[1]
(b) Energy is lost as heat at each trophic level (through respiration, movement, undigested waste). Only about 10% is transferred. There is insufficient energy to support another trophic level.
[2]
(c) Decomposers (bacteria and fungi) break down dead organisms and waste, recycling nutrients back into the environment for plants to reuse.
[1]
Question 32
(a) Stage A: Egg
Stage B: Larva
Stage C: Pupa
Stage D: Adult
[2]
(b) Complete metamorphosis (four distinct stages: egg, larva, pupa, adult; larva looks very different from adult).
[1]
(c) Mosquito: Larva and pupa live in water, breathe air through siphon/trumpet.
Frog: Tadpole lives in water, breathes through gills (later lungs).
Difference: Mosquito larvae/pupae are air-breathers (come to surface); frog tadpoles are water-breathers (gills).
[2]
Question 33
(a) Structural adaptation: Thick, waxy cuticle / Sunken stomata / Reduced leaves (spines) / Extensive shallow roots / Succulent stems.
(Any one)
[1]
(b) Behavioural adaptation: Stomata open at night (CAM photosynthesis) to reduce water loss / Dormancy during extreme drought.
(Any one)
[1]
(c) The adaptation reduces water loss (transpiration) and stores water, allowing the cactus to survive long periods without rain in the desert.
[1]
Question 34
(a) Bacteria and Fungi (mould/yeast)
[1]
(b) Decomposers break down dead organic matter and waste products into simpler substances (nutrients/mineral salts), returning them to the soil/air for producers (plants) to reuse. This recycles nutrients in the ecosystem.
[2]
(c) Without decomposers, dead matter and waste would accumulate, nutrients would be locked up and not recycled, plants would lack essential minerals, and the entire food web would collapse.
[2]
Question 35
(a) Vertebrates have a backbone (vertebral column); Invertebrates do not have a backbone.
[1]
(b) Animal P: Fish (gills, scales, fins, lay eggs in water)
Animal Q: Mammal (hair/fur, lungs, give birth to live young, produce milk)
[2]
(c) Bat (mammal) → has hair, gives birth to live young, feeds young milk, breathes with lungs.
Penguin (bird) → has feathers, lays eggs, breathes with lungs, beak.
Difference: Bat has hair/fur and gives live birth; Penguin has feathers and lays eggs.
[2]
Question 36
(a) Photosynthesis
[1]
(b) Carbon dioxide + Water → (Light + Chlorophyll) → Glucose + Oxygen
[1]
(c) Light intensity: Rate increases with light intensity until a maximum (saturation point).
Carbon dioxide concentration: Rate increases with CO₂ concentration until a maximum.
Temperature: Rate increases with temperature up to an optimum (~35°C), then decreases as enzymes denature.
(Any two factors with correct trend)
[2]
(d) Oxygen is released as a by-product, which animals and other organisms need for respiration to release energy from food.
[1]
Question 37
(a) Pollination: Transfer of pollen grains from anther to stigma.
Fertilisation: Fusion of male gamete (in pollen) with female gamete (in ovule) to form a zygote.
[2]
(b) Wind-pollinated: Small, dull petals; no nectar/scent; large feathery stigma; light, smooth pollen; long exposed stamens.
Insect-pollinated: Large, colourful petals; nectar/scent; sticky stigma; heavy, sticky pollen; stamens inside flower.
(Any two differences)
[2]
(c) After fertilisation, the ovary develops into the fruit and the ovules develop into seeds. The fruit protects the seeds and aids in seed dispersal.
[1]
Question 38
(a) Circulatory system: Transports oxygen, nutrients, hormones to cells and carbon dioxide, waste away from cells.
Respiratory system: Gaseous exchange – takes in oxygen, removes carbon dioxide.
Digestive system: Breaks down food into simple substances (nutrients) for absorption into the blood.
[3]
(b) Digested nutrients (glucose, amino acids) are absorbed in the small intestine into the bloodstream (circulatory system) and transported to all cells for respiration (with oxygen from respiratory system) to release energy.
[2]
(c) Exercise increases demand for energy → heart beats faster (circulatory) and breathing rate increases (respiratory) to supply more oxygen and glucose to muscles and remove more carbon dioxide.
[1]
MARKING GUIDELINES
- Section A: 2 marks per question (28 × 2 = 56 marks)
- Section B: Marks as indicated (Total 44 marks)
- Total: 100 marks
Key Concepts Tested:
- Diversity of Living Things (Classification, Characteristics)
- Cells (Plant vs Animal, Microorganisms)
- Life Cycles & Reproduction
- Adaptations (Structural vs Behavioural)
- Food Chains/Webs & Energy Flow
- Decomposers & Nutrient Cycling
- Plant Systems (Photosynthesis, Transport, Reproduction)
- Human Systems (Digestive, Circulatory, Respiratory)
- Interactions (Environment, Ecosystems)
End of Answer Key
Free quiz and exam paper access
Enter your details to view this paper
Your access is remembered on this device.