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Primary 6 PSLE Science Semestral Assessment 2 (End of Year) Paper 4

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TuitionGoWhere Practice Paper - Science Primary 6 PSLE

TuitionGoWhere Exam Practice (AI)

Subject: Science
Level: Primary 6 PSLE
Paper: SA2 Version 4
Duration: 1 h 45 min
Total Marks: 100

Name: ________________________
Class: ________________________
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: Multiple-Choice Questions (56 marks)

Questions 1 to 28 carry 2 marks each. For each question, four options are given. Choose the correct answer and shade the corresponding oval on the OAS.

1

Which of the following statements about the classification of living things is correct?

(1) All fungi are multicellular organisms. (2) Bacteria are classified under the kingdom Plantae. (3) All animals are multicellular and heterotrophic. (4) Protists are always unicellular organisms.

[2]

2

Study the classification chart below.

<image_placeholder> id: Q2-fig1 type: diagram linked_question: Q2 description: A dichotomous classification chart showing the grouping of organisms. The chart starts with "Living Things" branching into "Plants" and "Animals". Under "Plants", it branches into "Flowering" and "Non-flowering". Under "Animals", it branches into "Vertebrates" and "Invertebrates". Vertebrates further branch into "Mammals", "Birds", "Fish", "Reptiles", "Amphibians". Invertebrates branch into "Insects", "Arachnids", "Molluscs", "Worms". labels: Living Things, Plants, Animals, Flowering, Non-flowering, Vertebrates, Invertebrates, Mammals, Birds, Fish, Reptiles, Amphibians, Insects, Arachnids, Molluscs, Worms values: None must_show: Clear branching hierarchy with all labels visible </image_placeholder>

Which group of organisms is classified incorrectly in the chart?

(1) Mushroom under Non-flowering plants (2) Whale under Mammals (3) Spider under Arachnids (4) Earthworm under Worms

[2]

3

Four students made the following statements about microorganisms.

Student	Statement
Ali	All bacteria are harmful to humans.
Bala	Yeast is a type of fungus.
Cindy	Viruses can reproduce on their own.
Devi	All microorganisms can be seen with a light microscope.

Which student(s) made a correct statement?

(1) Bala only (2) Ali and Cindy only (3) Bala and Devi only (4) Ali, Cindy and Devi only

[2]

4

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

<image_placeholder> id: Q4-fig1 type: diagram linked_question: Q4 description: Two side-by-side diagrams. Left: Plant cell with cell wall, cell membrane, cytoplasm, nucleus, chloroplasts, large central vacuole. Right: Animal cell with cell membrane, cytoplasm, nucleus, small vacuoles, no cell wall, no chloroplasts. labels: Cell wall, Cell membrane, Cytoplasm, Nucleus, Chloroplast, Vacuole (large), Vacuole (small) values: None must_show: Clear labels on both cells showing all listed organelles </image_placeholder>

Which of the following statements is true about the structures found in both cells?

(1) Both cells have a cell wall. (2) Both cells have chloroplasts. (3) Both cells have a nucleus. (4) Both cells have a large central vacuole.

[2]

5

Which of the following groups of organisms are all decomposers?

(1) Mushroom, yeast, bacteria (2) Fern, moss, algae (3) Lion, eagle, shark (4) Grasshopper, rabbit, deer

[2]

6

Study the flowchart below.

<image_placeholder> id: Q6-fig1 type: diagram linked_question: Q6 description: A flowchart for classifying vertebrates. Start: "Does it have feathers?" Yes -> "Bird". No -> "Does it have hair/fur?" Yes -> "Mammal". No -> "Does it have moist skin?" Yes -> "Amphibian". No -> "Does it have dry scaly skin?" Yes -> "Reptile". No -> "Does it have gills and scales?" Yes -> "Fish". labels: Feathers, Hair/fur, Moist skin, Dry scaly skin, Gills and scales, Bird, Mammal, Amphibian, Reptile, Fish values: None must_show: Complete flowchart with all decision diamonds and outcome boxes </image_placeholder>

An animal has dry scaly skin and lays eggs with leathery shells. Which group does it belong to?

(1) Amphibian (2) Bird (3) Reptile (4) Mammal

[2]

7

Which of the following is a characteristic of all insects?

(1) They have two pairs of wings. (2) They have three body parts and six legs. (3) They undergo complete metamorphosis. (4) They live on land only.

[2]

8

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	✓	✗	✗	✗
Multicellular	✓	✓	✓	✓
Heterotrophic	✗	✓	✓	✓

Which organism is most likely a fungus?

(1) P (2) Q (3) R (4) S

[2]

9

Which of the following statements about viruses is correct?

(1) Viruses are made of cells. (2) Viruses can carry out respiration. (3) Viruses reproduce only inside living cells. (4) Viruses are classified under the kingdom Monera.

[2]

10

Study the diagram of a food web below.

<image_placeholder> id: Q10-fig1 type: diagram linked_question: Q10 description: A food web diagram. Producers: Grass, Oak Tree. Primary Consumers: Grasshopper (eats grass), Rabbit (eats grass), Caterpillar (eats oak leaves). Secondary Consumers: Frog (eats grasshopper), Bird (eats grasshopper, caterpillar), Snake (eats frog, rabbit). Tertiary Consumer: Hawk (eats snake, bird). Decomposers: Bacteria, Fungi (break down all dead organisms). labels: Grass, Oak Tree, Grasshopper, Rabbit, Caterpillar, Frog, Bird, Snake, Hawk, Bacteria, Fungi values: None must_show: All organisms with arrows showing energy flow from producers to tertiary consumer and decomposers </image_placeholder>

How many food chains in the food web have exactly four organisms (including the producer)?

(1) 2 (2) 3 (3) 4 (4) 5

[2]

11

Which of the following adaptations is a structural adaptation?

(1) A bird migrating south for winter. (2) A chameleon changing its skin colour. (3) A cactus having spines instead of leaves. (4) A bear hibernating during winter.

[2]

12

The diagram below shows the life cycle of a butterfly.

<image_placeholder> id: Q12-fig1 type: diagram linked_question: Q12 description: A circular diagram showing four stages: Egg -> Larva (Caterpillar) -> Pupa (Chrysalis) -> Adult Butterfly -> back to Egg. Arrows indicate direction. labels: Egg, Larva (Caterpillar), Pupa (Chrysalis), Adult Butterfly values: None must_show: Clear four-stage cycle with arrows and labels </image_placeholder>

Which stage is the feeding and growing stage?

(1) Egg (2) Larva (3) Pupa (4) Adult

[2]

13

Which of the following organisms reproduces by spores?

(1) Fern (2) Mango tree (3) Hibiscus plant (4) Papaya tree

[2]

14

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	Salmon	Wet scales	Gills	Lay eggs in water
D	Bat	Fur/Hair	Lungs	Give birth to young

Which group represents mammals?

(1) A (2) B (3) C (4) D

[2]

15

Which of the following is NOT a characteristic of flowering plants?

(1) They produce seeds enclosed in fruits. (2) They have vascular tissues. (3) They reproduce by spores. (4) They have roots, stems and leaves.

[2]

16

The diagram below shows a microorganism viewed under a microscope.

<image_placeholder> id: Q16-fig1 type: diagram linked_question: Q16 description: A single-celled organism with irregular shape, nucleus, contractile vacuole, food vacuole, cell membrane, cytoplasm. No cell wall, no chloroplasts. labels: Nucleus, Contractile vacuole, Food vacuole, Cell membrane, Cytoplasm values: None must_show: Clear amoeba-like shape with all labeled organelles </image_placeholder>

Which kingdom does this organism most likely belong to?

(1) Plantae (2) Animalia (3) Fungi (4) Protista

[2]

17

Which of the following pairs shows the correct matching of organism to its kingdom?

	Organism	Kingdom
(1)	Mushroom	Plantae
(2)	Bacteria	Monera
(3)	Amoeba	Fungi
(4)	Moss	Animalia

[2]

18

Study the food chain below.

Grass → Grasshopper → Frog → Snake → Hawk

If a disease kills all the frogs, what will most likely happen to the grass population?

(1) Increase (2) Decrease (3) Remain the same (4) Die out completely

[2]

19

Which of the following statements about bacteria is correct?

(1) All bacteria cause diseases. (2) Bacteria have a nucleus. (3) Bacteria reproduce by binary fission. (4) Bacteria are multicellular organisms.

[2]

20

The diagram below shows a plant.

<image_placeholder> id: Q20-fig1 type: diagram linked_question: Q20 description: A plant with needle-like leaves, woody stem, cones (no flowers), seeds exposed on cone scales. labels: Needle-like leaves, Woody stem, Cones, Exposed seeds values: None must_show: Clear gymnosperm features: needles, cones, exposed seeds </image_placeholder>

This plant is classified as a:

(1) Fern (2) Moss (3) Gymnosperm (4) Angiosperm

[2]

21

Which of the following is a behavioural adaptation?

(1) Thick fur on a polar bear (2) Webbed feet on a duck (3) Birds flying in a V-formation (4) Camouflage colouring on a stick insect

[2]

22

Study the table below showing characteristics of five vertebrates.

Animal	Body Covering	Breathing Organ	Reproduction	Body Temperature
W	Feathers	Lungs	Lay eggs	Constant
X	Fur	Lungs	Give birth	Constant
Y	Scales	Gills	Lay eggs	Varies
Z	Moist skin	Lungs, skin	Lay eggs	Varies

Which animal is a bird?

(1) W (2) X (3) Y (4) Z

[2]

23

Which of the following organisms is a producer in a food chain?

(1) Lion (2) Grass (3) Deer (4) Mushroom

[2]

24

The diagram below shows the structure of a typical bacterium.

<image_placeholder> id: Q24-fig1 type: diagram linked_question: Q24 description: A rod-shaped bacterial cell showing: cell wall, cell membrane, cytoplasm, nucleoid (no nuclear membrane), ribosomes, flagellum, plasmid. No nucleus, no mitochondria, no chloroplasts. labels: Cell wall, Cell membrane, Cytoplasm, Nucleoid, Ribosomes, Flagellum, Plasmid values: None must_show: Prokaryotic features clearly shown: no nucleus, nucleoid region, flagellum </image_placeholder>

Which structure is absent in a bacterial cell?

(1) Cell wall (2) Cell membrane (3) Nucleus (4) Cytoplasm

[2]

25

Which of the following groups contains only invertebrates?

(1) Snake, lizard, crocodile (2) Earthworm, snail, spider (3) Frog, toad, salamander (4) Shark, salmon, tuna

[2]

26

Study the dichotomous key below.

a) Has backbone ................... Go to 2 b) No backbone ................... Go to 3
a) Has feathers ................... Bird b) Has hair/fur ................... Mammal
a) Has jointed legs ................... Insect b) No jointed legs ................... Worm

An animal has a backbone and hair. What is it?

(1) Bird (2) Mammal (3) Insect (4) Worm

[2]

27

Which of the following statements about fungi is correct?

(1) All fungi are unicellular. (2) Fungi make their own food by photosynthesis. (3) Fungi reproduce by spores. (4) Fungi have chlorophyll.

[2]

28

The diagram below shows a food pyramid.

<image_placeholder> id: Q28-fig1 type: diagram linked_question: Q28 description: A pyramid with four levels. Bottom (largest): Producers (Plants). Second: Primary Consumers (Herbivores). Third: Secondary Consumers (Carnivores). Top (smallest): Tertiary Consumers (Top Carnivores). labels: Producers, Primary Consumers, Secondary Consumers, Tertiary Consumers values: None must_show: Pyramid shape with four labeled levels, decreasing width upward </image_placeholder>

Which statement about the food pyramid is correct?

(1) Energy increases at each higher level. (2) The number of organisms increases at each higher level. (3) The amount of energy transferred to the next level is about 10%. (4) Tertiary consumers have the most energy available.

[2]

Section B: Open-Ended Questions (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.

29

The diagram below shows two organisms, A and B.

<image_placeholder> id: Q29-fig1 type: diagram linked_question: Q29 description: Two organisms side by side. Organism A: A tree with broad leaves, flowers, fruits containing seeds. Organism B: A fern with fronds, no flowers, no fruits, sori (spore clusters) on underside of fronds. labels: Organism A: Flowers, Fruits, Seeds, Broad leaves. Organism B: Fronds, Sori (spores), Rhizome, Roots values: None must_show: Clear contrast between flowering plant (angiosperm) and fern (pteridophyte) </image_placeholder>

(a) State one similarity between Organism A and Organism B in terms of how they obtain food. [1]

(b) State two differences between Organism A and Organism B in terms of reproduction. [2]

(c) Organism B is classified as a non-flowering plant. Name the group of non-flowering plants that Organism B belongs to. [1]

30

Study the classification chart below.

<image_placeholder> id: Q30-fig1 type: diagram linked_question: Q30 description: A classification chart with missing labels. Top: "Vertebrates". Five branches: Group 1, Group 2, Group 3, Group 4, Group 5. Each group has a box for "Example" and "Body Covering". labels: Vertebrates, Group 1, Group 2, Group 3, Group 4, Group 5, Example, Body Covering values: None must_show: Five empty groups under Vertebrates with Example and Body Covering boxes for each </image_placeholder>

(a) Fill in the names of the five groups of vertebrates in the chart above. [2]

(b) For each group, state one example and its body covering. [5]

31

The diagram below shows a food web in a pond community.

<image_placeholder> id: Q31-fig1 type: diagram linked_question: Q31 description: Pond food web. Producers: Phytoplankton, Water lily. Primary Consumers: Water flea (eats phytoplankton), Tadpole (eats water lily), Snail (eats water lily). Secondary Consumers: Small fish (eats water flea, tadpole), Dragonfly nymph (eats water flea, snail). Tertiary Consumer: Large fish (eats small fish, dragonfly nymph). Decomposers: Bacteria, Fungi. labels: Phytoplankton, Water lily, Water flea, Tadpole, Snail, Small fish, Dragonfly nymph, Large fish, Bacteria, Fungi values: None must_show: All organisms with correct feeding arrows </image_placeholder>

(a) Write down a food chain with four organisms from the food web. [1]

(b) If all the water fleas are removed from the pond, explain what will happen to the population of small fish. [2]

32

The table below shows the characteristics of four organisms, W, X, Y and Z.

Characteristic	W	X	Y	Z
Made of cells	Yes	Yes	Yes	Yes
Has nucleus	Yes	Yes	Yes	No
Has cell wall	Yes	No	Yes	Yes
Has chloroplasts	Yes	No	No	No
Mode of nutrition	Autotrophic	Heterotrophic	Heterotrophic	Heterotrophic

(a) Which organism(s) is/are plant(s)? Explain your answer. [2]

(b) Which organism is most likely a bacterium? Explain your answer. [2]

33

The diagram below shows the life cycle of a mosquito.

<image_placeholder> id: Q33-fig1 type: diagram linked_question: Q33 description: Four-stage life cycle: Egg -> Larva (Wriggler) -> Pupa (Tumbler) -> Adult Mosquito. Eggs laid on water surface. Larva and pupa live in water. Adult flies. labels: Egg, Larva (Wriggler), Pupa (Tumbler), Adult Mosquito values: None must_show: Four stages with habitat labels (water/air) </image_placeholder>

(a) Name the type of metamorphosis shown by the mosquito. [1]

(b) State one difference between the larva and the pupa in terms of feeding. [1]

(c) Mosquitoes spread diseases like dengue. Suggest one way to control the mosquito population by targeting a specific stage of its life cycle. Explain how it works. [2]

34

Study the diagram of a plant cell below.

<image_placeholder> id: Q34-fig1 type: diagram linked_question: Q34 description: A plant cell with labeled parts: A - Cell wall, B - Cell membrane, C - Cytoplasm, D - Nucleus, E - Chloroplast, F - Large central vacuole. labels: A: Cell wall, B: Cell membrane, C: Cytoplasm, D: Nucleus, E: Chloroplast, F: Large central vacuole values: None must_show: All six structures clearly labeled </image_placeholder>

(a) Name the parts labeled A, D and E. [1.5]

(b) State the function of part F. [1]

(d) Which labeled part controls all activities in the cell? [1]

35

The diagram below shows an experiment set-up to investigate the conditions needed for germination.

<image_placeholder> id: Q35-fig1 type: experimental_setup linked_question: Q35 description: Four test tubes in a rack. Tube 1: Dry cotton wool + seeds, at room temperature. Tube 2: Wet cotton wool + seeds, in freezer (0°C). Tube 3: Wet cotton wool + seeds, at room temperature. Tube 4: Wet cotton wool + boiled seeds (dead), at room temperature. All tubes open to air. labels: Tube 1: Dry, Room temp; Tube 2: Wet, 0°C; Tube 3: Wet, Room temp; Tube 4: Wet, Room temp, Boiled seeds values: None must_show: Four test tubes with clear labels showing conditions </image_placeholder>

(a) In which test tube(s) will the seeds germinate? [1]

(b) Explain why the seeds in Test Tube 1 did not germinate. [1]

(d) What is the purpose of Test Tube 4? [1]

36

The diagram below shows a microorganism.

<image_placeholder> id: Q36-fig1 type: diagram linked_question: Q36 description: A yeast cell budding. Parent cell with nucleus, bud forming with nucleus dividing, cell wall, cytoplasm. labels: Parent cell, Bud (daughter cell), Nucleus, Cytoplasm, Cell wall values: None must_show: Clear budding process with nucleus division </image_placeholder>

(a) Name the microorganism shown. [1]

(b) Name the type of asexual reproduction shown. [1]

(d) This microorganism can respire anaerobically. Write the word equation for anaerobic respiration in yeast. [1]

37

Study the food chain below.

Phytoplankton → Zooplankton → Small Fish → Large Fish → Shark

The diagram below shows a pyramid of numbers for this food chain.

<image_placeholder> id: Q37-fig1 type: diagram linked_question: Q37 description: An inverted pyramid of numbers. Bottom (widest): Phytoplankton (1,000,000). Second: Zooplankton (100,000). Third: Small Fish (1,000). Fourth: Large Fish (100). Top: Shark (10). labels: Phytoplankton, Zooplankton, Small Fish, Large Fish, Shark values: Phytoplankton: 1,000,000; Zooplankton: 100,000; Small Fish: 1,000; Large Fish: 100; Shark: 10 must_show: Inverted pyramid with numbers labeled at each level </image_placeholder>

(a) Explain why the pyramid of numbers is inverted (widest at the bottom). [1]

(b) If a pyramid of biomass were drawn for the same food chain, would it be inverted? Explain your answer. [2]

(c) Only about 10% of energy is transferred from one trophic level to the next. Calculate the approximate percentage of energy from phytoplankton that reaches the shark. [1]

38

The diagram below shows two organisms, P and Q.

<image_placeholder> id: Q38-fig1 type: diagram linked_question: Q38 description: Organism P: Mushroom with cap, gills, stalk, mycelium underground. Organism Q: Bracket fungus on tree trunk, shelf-like, pores underneath. labels: P: Cap, Gills, Stalk, Mycelium. Q: Fruiting body (shelf), Pores, Mycelium inside wood values: None must_show: Two different fungi: mushroom with gills, bracket fungus with pores </image_placeholder>

(a) State the kingdom that both organisms belong to. [1]

(b) State one similarity in how Organism P and Organism Q obtain nutrients. [1]

(d) Are fungi classified as plants? Explain your answer. [2]

39

The table below shows the characteristics of three plants, X, Y and Z.

Characteristic	X	Y	Z
Has true roots, stems, leaves	Yes	Yes	No
Has vascular tissues	Yes	Yes	No
Reproduces by seeds	Yes	No	No
Reproduces by spores	No	Yes	Yes

(a) Which plant(s) is/are non-flowering plants? [1]

(b) Plant X produces seeds in cones. Name the group of plants that Plant X belongs to. [1]

(d) Plant Y is a fern. Where are the spores of a fern produced? [1]

40

Study the dichotomous key below used to classify five animals: Eagle, Bat, Whale, Penguin, Guppy.

a) Lives in water ................... Go to 2 b) Lives on land/air ................... Go to 3
a) Breathes with gills ................... Guppy b) Breathes with lungs ................... Whale
a) Has feathers ................... Go to 4 b) Has hair/fur ................... Bat
a) Can fly ................... Eagle b) Cannot fly ................... Penguin

(a) Using the key, identify the animal that has feathers and cannot fly. [1]

(b) State one similarity and one difference between the bat and the whale. [2]

41

The diagram below shows a cell.

<image_placeholder> id: Q41-fig1 type: diagram linked_question: Q41 description: An animal cell with labeled parts: A - Cell membrane, B - Cytoplasm, C - Nucleus, D - Mitochondrion, E - Small vacuole. labels: A: Cell membrane, B: Cytoplasm, C: Nucleus, D: Mitochondrion, E: Small vacuole values: None must_show: Animal cell with five labeled parts </image_placeholder>

(a) Is this a plant cell or an animal cell? Give a reason for your answer. [1]

(b) Name the part where respiration takes place. [1]

(d) Part A is partially permeable. Explain what this means. [1]

42

The diagram below shows a food web in a forest ecosystem.

<image_placeholder> id: Q42-fig1 type: diagram linked_question: Q42 description: Forest food web. Producers: Oak tree, Grass, Berries. Primary Consumers: Caterpillar (oak), Grasshopper (grass), Deer (grass, berries), Mouse (berries, grass). Secondary Consumers: Bird (caterpillar, grasshopper), Snake (mouse, bird), Fox (mouse, deer). Tertiary Consumer: Hawk (snake, bird, fox). Decomposers: Fungi, Bacteria. labels: Oak tree, Grass, Berries, Caterpillar, Grasshopper, Deer, Mouse, Bird, Snake, Fox, Hawk, Fungi, Bacteria values: None must_show: Complex web with multiple connections, decomposers linked to all dead organisms </image_placeholder>

(a) How many food chains in the food web have the oak tree as the producer? [1]

(b) The population of grasshoppers decreases due to a pesticide. Explain how this affects the population of snakes. [2]

(d) Explain why decomposers are important in this ecosystem. [2]

43

The diagram below shows the structure of a flower.

<image_placeholder> id: Q43-fig1 type: diagram linked_question: Q43 description: A longitudinal section of a flower showing: Sepal, Petal, Stamen (Anther, Filament), Carpel (Stigma, Style, Ovary, Ovule), Receptacle, Pedicel. labels: Sepal, Petal, Anther, Filament, Stigma, Style, Ovary, Ovule, Receptacle, Pedicel values: None must_show: Complete flower structure with all reproductive parts labeled </image_placeholder>

(a) Name the male reproductive part of the flower. [1]

(b) Name the part that produces pollen grains. [1]

(d) After fertilisation, which part develops into the seed? [1]

(e) State one function of the petals. [1]

44

Study the table below showing the characteristics of four organisms.

Organism	Kingdom	Cell Type	Number of Cells	Nutrition
A	Monera	Prokaryotic	Unicellular	Autotrophic / Heterotrophic
B	Protista	Eukaryotic	Mostly unicellular	Autotrophic / Heterotrophic
C	Fungi	Eukaryotic	Multicellular (mostly)	Heterotrophic (saprotrophic)
D	Plantae	Eukaryotic	Multicellular	Autotrophic

(a) Organism A is a bacterium. State one difference between a prokaryotic cell and a eukaryotic cell. [1]

(b) Organism C is a mould. Explain how it obtains nutrients. [1]

(d) Viruses are not classified in any of the five kingdoms. State one reason why. [1]

45

The diagram below shows an animal.

<image_placeholder> id: Q45-fig1 type: diagram linked_question: Q45 description: A penguin standing on ice. Features: Feathers, Wings modified as flippers, Webbed feet, Thick layer of fat, Streamlined body, Counter-shading (black back, white belly). labels: Feathers, Flippers, Webbed feet, Blubber (fat), Streamlined body, Counter-shading values: None must_show: All labeled adaptations </image_placeholder>

(a) State the vertebrate group this animal belongs to. [1]

(b) The penguin has wings but cannot fly. Explain how its wings are adapted for its environment. [1]

(d) The penguin has black feathers on its back and white feathers on its belly. Explain how this colouration helps it survive. [1]

46

The diagram below shows a food chain in a grassland ecosystem.

Grass → Grasshopper → Frog → Snake → Eagle

(a) Identify the producer in this food chain. [1]

(b) If eagles are hunted until they become extinct, explain what will happen to the population of snakes in the short term and long term. [2]

(d) Explain why the pyramid of energy is always upright (never inverted). [1]

47

The diagram below shows a microorganism viewed under a microscope.

<image_placeholder> id: Q47-fig1 type: diagram linked_question: Q47 description: A paramecium: Slipper-shaped, covered in cilia, oral groove, gullet, macronucleus, micronucleus, contractile vacuole (two), food vacuoles, pellicle. labels: Cilia, Oral groove, Gullet, Macronucleus, Micronucleus, Contractile vacuole, Food vacuole, Pellicle values: None must_show: Paramecium shape with all organelles labeled </image_placeholder>

(a) Name the kingdom this organism belongs to. [1]

(b) Name the structure used for movement. [1]

(d) This organism reproduces asexually by binary fission. Describe what happens during binary fission. [2]

48

Study the classification chart below.

<image_placeholder> id: Q48-fig1 type: diagram linked_question: Q48 description: A chart showing the five kingdoms. Center: "Living Things". Five branches: Monera, Protista, Fungi, Plantae, Animalia. Each kingdom has boxes for: Cell Type, Cell Wall, Nutrition, Example. labels: Monera, Protista, Fungi, Plantae, Animalia, Cell Type, Cell Wall, Nutrition, Example values: None must_show: Five kingdoms with empty property boxes </image_placeholder>

(a) Complete the chart for the kingdom Fungi by filling in:

Cell Type: ___________
Cell Wall: ___________ (material)
Nutrition: ___________
Example: ___________ [2]

(b) State two differences between organisms in kingdom Plantae and kingdom Animalia. [2]

(c) Bacteria are placed in kingdom Monera. State one characteristic of bacteria that is different from organisms in the other four kingdoms. [1]

End of Paper

Answers

TuitionGoWhere Practice Paper - Science Primary 6 PSLE (Answer Key)

TuitionGoWhere Exam Practice (AI)

Subject: Science
Level: Primary 6 PSLE
Paper: SA2 Version 4
Total Marks: 100

Section A: Multiple-Choice Questions (56 marks)

1

Answer: (3) All animals are multicellular and heterotrophic.
Explanation: Animals are defined as multicellular, eukaryotic organisms that are heterotrophic (obtain food by consuming other organisms).

(1) is incorrect: Some fungi (e.g., yeast) are unicellular.
(2) is incorrect: Bacteria belong to kingdom Monera, not Plantae.
(4) is incorrect: Some protists (e.g., seaweed) are multicellular.

2

Answer: (1) Mushroom under Non-flowering plants
Explanation: Mushrooms are fungi, not plants. They do not photosynthesise and have cell walls made of chitin, not cellulose. They belong to kingdom Fungi, not Plantae.

3

Answer: (1) Bala only
Explanation:

Ali: Incorrect. Many bacteria are beneficial (e.g., gut bacteria, decomposers, nitrogen-fixing bacteria).
Bala: Correct. Yeast is a unicellular fungus.
Cindy: Incorrect. Viruses cannot reproduce on their own; they need a host cell.
Devi: Incorrect. Viruses are too small to be seen with a light microscope; they require an electron microscope.

4

Answer: (3) Both cells have a nucleus.
Explanation: Both plant and animal cells are eukaryotic and have a true nucleus.

(1) Only plant cells have a cell wall (made of cellulose).
(2) Only plant cells have chloroplasts (for photosynthesis).
(4) Plant cells have a large central vacuole; animal cells have small, temporary vacuoles.

5

Answer: (1) Mushroom, yeast, bacteria
Explanation: Decomposers break down dead organic matter. Mushrooms (fungi), yeast (fungi), and bacteria are all decomposers. The other groups are producers (plants) or consumers (animals).

6

Answer: (3) Reptile
Explanation: The flowchart shows: dry scaly skin → Reptile. Reptiles have dry scaly skin and lay eggs with leathery shells (e.g., snakes, lizards, turtles).

7

Answer: (2) They have three body parts and six legs.
Explanation: All insects have three body parts (head, thorax, abdomen) and six legs. This is a defining characteristic.

(1) Some insects are wingless (e.g., fleas, lice) or have one pair of wings (e.g., flies).
(3) Some insects undergo incomplete metamorphosis (e.g., grasshoppers, cockroaches).
(4) Some insects live in water during larval stages (e.g., mosquito larvae).

8

Answer: (2) Q
Explanation: Fungi have cell walls (made of chitin), no chloroplasts (heterotrophic), are multicellular (mostly), and are heterotrophic. Organism Q matches: cell wall ✓, chloroplasts ✗, multicellular ✓, heterotrophic ✓.

9

Answer: (3) Viruses reproduce only inside living cells.
Explanation: Viruses are obligate intracellular parasites. They lack cellular machinery for reproduction and must hijack a host cell's machinery to replicate.

(1) Viruses are acellular (not made of cells).
(2) Viruses do not carry out respiration.
(4) Viruses are not classified in any kingdom; they are non-living outside a host.

10

Answer: (3) 4
Explanation: Food chains with exactly 4 organisms (producer + 3 consumers):

Grass → Grasshopper → Frog → Snake
Grass → Grasshopper → Bird → Hawk
Grass → Rabbit → Snake → Hawk
Oak Tree → Caterpillar → Bird → Hawk
(

<stage3_exam_answers_md>

TuitionGoWhere Practice Paper - Science Primary 6 PSLE (Answer Key)

TuitionGoWhere Exam Practice (AI)

Subject: Science
Level: Primary 6 PSLE
Paper: SA2 Version 4

Section A: Multiple-Choice Questions (56 marks)

Question	Answer	Explanation
1	(3)	All animals are multicellular and heterotrophic. Fungi can be unicellular (yeast). Bacteria are in Kingdom Monera, not Plantae. Protists can be multicellular (e.g., seaweed).
2	(1)	Mushroom is a fungus, not a plant. It should not be classified under non-flowering plants. Whale is a mammal, spider is an arachnid, earthworm is a worm - all correct.
3	(1)	Bala only. Yeast is a fungus. Ali: Not all bacteria are harmful (some are beneficial). Cindy: Viruses cannot reproduce on their own; they need a host cell. Devi: Viruses cannot be seen with a light microscope; they need an electron microscope.
4	(3)	Both plant and animal cells have a nucleus. Plant cells have cell wall, chloroplasts, and large central vacuole; animal cells do not.
5	(1)	Mushroom (fungus), yeast (fungus), and bacteria are all decomposers. Others are producers (2), carnivores (3), or herbivores (4).
6	(3)	Dry scaly skin and leathery eggs are characteristics of reptiles.
7	(2)	All insects have three body parts (head, thorax, abdomen) and six legs. Not all have wings (e.g., fleas), not all undergo complete metamorphosis (some incomplete), and some live in water (e.g., water strider).
8	(2)	Organism Q: Has cell wall (fungi/plants), no chloroplasts (not plant), multicellular, heterotrophic (fungi). Fungi have cell walls made of chitin, are heterotrophic, and multicellular (except yeast).
9	(3)	Viruses reproduce only inside living cells (obligate intracellular parasites). They are not made of cells, cannot carry out respiration, and are not classified in any kingdom (non-living).
10	(3)	Food chains with exactly 4 organisms: 1) Grass → Grasshopper → Frog → Snake, 2) Grass → Grasshopper → Bird → Hawk, 3) Oak Tree → Caterpillar → Bird → Hawk, 4) Grass → Rabbit → Snake → Hawk. Total = 4.
11	(3)	Cactus having spines instead of leaves is a structural (physical) adaptation. Others are behavioural adaptations.
12	(2)	Larva (caterpillar) is the feeding and growing stage.
13	(1)	Ferns reproduce by spores. Mango, hibiscus, papaya are flowering plants (seeds in fruits).
14	(4)	Group D (Bat) has fur/hair, lungs, gives birth to young - characteristics of mammals.
15	(3)	Flowering plants reproduce by seeds (in fruits), not spores. They have vascular tissues, roots, stems, leaves.
16	(4)	Amoeba-like: single-celled, nucleus, contractile vacuole, food vacuole, no cell wall, no chloroplasts → Kingdom Protista.
17	(2)	Bacteria belong to Kingdom Monera. Mushroom → Fungi, Amoeba → Protista, Moss → Plantae.
18	(1)	Frogs eat grasshoppers. If frogs die, grasshopper population increases → more grass eaten → grass population decreases? Wait: Grass → Grasshopper → Frog. No frogs → more grasshoppers → more grass eaten → grass decreases. But the question asks about grass population. Let's trace: Grass (producer) → Grasshopper (primary consumer) → Frog (secondary consumer) → Snake → Hawk. If frogs die, grasshoppers increase (less predation), so grass decreases. But the answer key says (1) Increase? Let's re-read: "If a disease kills all the frogs, what will most likely happen to the grass population?" Grass → Grasshopper → Frog. No frogs → grasshoppers increase → grass decreases. So answer should be (2) Decrease. But standard textbook question: remove predator → prey increases → producer decreases. So (2) Decrease. However, some questions have trick: if frog eats grasshopper, and grasshopper eats grass. No frog → more grasshopper → less grass. So grass decreases. Answer: (2). But wait, the provided answer in the initial thought was (1). Let me double-check. Food chain: Grass → Grasshopper → Frog → Snake → Hawk. Frog is predator of grasshopper. Remove frog → grasshopper population increases → grass population decreases. So answer is (2) Decrease. I will put (2).
19	(3)	Bacteria reproduce by binary fission (asexual). Not all cause disease, they lack nucleus (prokaryotes), and are unicellular.
20	(3)	Needle-like leaves, cones, exposed seeds (no flowers/fruits) → Gymnosperm.
21	(3)	Birds flying in V-formation is a behavioural adaptation. Others are structural.
22	(1)	W: Feathers, lungs, lay eggs, constant body temperature → Bird. X: Mammal. Y: Fish. Z: Amphibian.
23	(2)	Grass is a producer (photosynthesizes). Lion (carnivore), Deer (herbivore), Mushroom (decomposer).
24	(3)	Bacteria are prokaryotes; they lack a true nucleus (have nucleoid instead). They have cell wall, cell membrane, cytoplasm.
25	(2)	Earthworm (annelid), snail (mollusc), spider (arachnid) are all invertebrates. Others are vertebrates.
26	(2)	Has backbone → Go to 2. Has hair/fur → Mammal.
27	(3)	Fungi reproduce by spores. Fungi can be multicellular (moulds) or unicellular (yeast). They are heterotrophic (saprotrophic), no chlorophyll.
28	(3)	Energy transfer between trophic levels is about 10% (Lindeman's 10% rule). Energy decreases at higher levels, number of organisms generally decreases, tertiary consumers have least energy.

Section B: Open-Ended Questions (44 marks)

29

(a) Both Organism A and Organism B are plants and make their own food through photosynthesis. / Both are autotrophs/producers. [1]

(b)

Organism A reproduces by seeds (enclosed in fruits/flowers), while Organism B reproduces by spores (found in sori on fronds).
Organism A produces flowers and fruits for reproduction, while Organism B does not produce flowers or fruits. [2]

(c) Ferns / Pteridophytes [1]

30

(a) The five groups of vertebrates are: Fish, Amphibians, Reptiles, Birds, Mammals. [2] (Any order, but typically this sequence)

(b) [5] (1 mark each for correct example + body covering pair)

Group	Example	Body Covering
Fish	Salmon / Guppy / Shark	Wet scales / Scales
Amphibians	Frog / Toad / Salamander	Moist skin / Permeable skin
Reptiles	Snake / Lizard / Turtle / Crocodile	Dry scales / Scales
Birds	Eagle / Sparrow / Penguin	Feathers
Mammals	Human / Dog / Bat / Whale	Fur / Hair

31

(a) Phytoplankton → Water flea → Small fish → Large fish
OR Water lily → Tadpole → Small fish → Large fish
OR Water lily → Snail → Dragonfly nymph → Large fish
(Any valid 4-organism chain from the web) [1]

(b) The population of small fish will decrease. Water fleas are a food source for small fish. If water fleas are removed, small fish lose one of their food sources (they also eat tadpoles), leading to less food available, so their population decreases. [2]

(c) Bacteria and fungi are decomposers. They break down dead organisms and waste materials, returning nutrients to the environment for producers (phytoplankton, water lily) to reuse. [1]

32

(a) Organism W is a plant.
Explanation: It is made of cells, has a nucleus, has a cell wall, has chloroplasts, and is autotrophic (makes its own food by photosynthesis). These are characteristics of plant cells. [2]

(b) Organism Z is most likely a bacterium.
Reason: It is made of cells but lacks a nucleus (prokaryotic), has a cell wall, lacks chloroplasts, and is heterotrophic. These are characteristics of bacteria (Kingdom Monera). [2]

(c) Organism X is most likely an animal.
Reason: It has a nucleus, lacks a cell wall, lacks chloroplasts, and is heterotrophic. These are characteristics of animal cells. [1]

(d) Organism Y is most likely a fungus (e.g., mushroom/mould).
Reason: It has a nucleus, has a cell wall (made of chitin), lacks chloroplasts, and is heterotrophic (saprotrophic). These are characteristics of fungi. [1]

33

The diagram shows the life cycle of a mosquito (complete metamorphosis).

(a) Stage X: Pupa [1]

(b) The larva (wriggler) lives in water and breathes through a siphon/tube at its posterior end (or "comes to the water surface to breathe air through a breathing tube"). [1]

(c) Stage Y: Adult mosquito [1]

(d) The adult female mosquito lays eggs in stagnant water (or "on the surface of stagnant water"). [1]

(e) Method: Remove/cover stagnant water (e.g., in flower pots, containers, drains).
Explanation: Mosquitoes lay eggs in stagnant water. Removing stagnant water prevents mosquitoes from breeding, thus breaking the life cycle and controlling the population. [2]

34

(a) Process A: Photosynthesis [1]

(b) Gas X: Oxygen [1]

(c) Process B: Respiration [1]

(d) Gas Y: Carbon dioxide [1]

(e) During the day, both photosynthesis and respiration occur in plants. The rate of photosynthesis is higher than the rate of respiration, so there is a net uptake of carbon dioxide and net release of oxygen. At night, only respiration occurs (no light for photosynthesis), so plants take in oxygen and give out carbon dioxide. [2]

35

(a) Part P: Stigma [1]

(b) Function of Part Q (Style): It connects the stigma to the ovary and provides a pathway for the pollen tube to grow from the stigma down to the ovary for fertilisation. [1]

(c) After fertilisation:

The ovule develops into the seed.
The ovary develops into the fruit. [2]

(d) Wind dispersal (or "by wind").
Characteristic: The seeds are small and light / have wing-like structures / feathery/hairy structures (e.g., dandelion, angsana) that allow them to be carried by wind. [2]

36

(a) Circuit A: The bulb does not light up / remains unlit.
Reason: The switch is open (off), so the circuit is incomplete/open. Electric current cannot flow through the circuit. [2]

(b) Circuit B: The bulb lights up.
Reason: The switch is closed (on), so the circuit is complete/closed. Electric current can flow from the battery, through the wires and switch, to the bulb and back. [2]

(c) Arrangement: Parallel [1]

(d) Advantage: If one bulb fuses/blows, the other bulb(s) will still light up (independent control). / Each bulb receives the full voltage from the battery and shines with maximum brightness. (Any one valid advantage) [1]

(e) Material for wire: Copper / Aluminium / Metal
Reason: It is a good conductor of electricity (allows electric current to pass through easily). [1]

37

(a) Force: Frictional force / Friction [1]

(b) The rougher the surface, the greater the frictional force, so the shorter the distance travelled by the toy car. / The smoother the surface, the less the frictional force, so the longer the distance travelled. [1]

(c) Gravitational force (pulls the car down the ramp) and Frictional force (between wheels/axles and between car and ramp surface, opposes motion). [2]

(d) Increase the height of the ramp (increases gravitational potential energy → more kinetic energy → travels further).
OR Use a smoother surface for the ramp/floor (reduces friction).
OR Reduce the mass of the car (less friction if friction depends on weight, but usually increasing height is the standard answer). [1]

38

(a) Material for part X: Metal / Copper / Aluminium / Steel
Reason: It is a good conductor of heat, so it transfers heat quickly from the stove to the food for fast cooking. [1]

(b) Material for part Y: Plastic / Wood / Rubber / Bakelite
Reason: It is a poor conductor of heat (good insulator), so it does not get hot easily, allowing the user to hold the handle safely without getting burnt. [1]

(c) Process: Conduction [1]

(d) The metal base (X) expands when heated. The glass/ceramic pot placed on it may not expand as much or as quickly. If the pot is cold and the base is very hot, the uneven expansion or rapid heating can cause the glass/ceramic to crack/shatter due to thermal stress. [2]

End of Answer Key