P6 Science (PSLE) Practice Worksheet

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Section A - Multiple Choice

A1.Which statement about forces acting on an object is correct?[1]

(a)Only one force can act on an object at any moment

(b)An object can only have a force act on it while a person is touching it

(c)More than one force can act on an object at the same time

(d)A force can only ever push, never pull

A2.Which of the following best explains why oil spills at sea are harmful to the environment?[1]

(a)Oil helps marine plants grow faster

(b)Oil increases the amount of oxygen in the water

(c)Oil makes seawater taste better for fish

(d)Oil coats the feathers and fur of marine animals and can poison them

A3.In a forest food chain, oak leaves -> caterpillar -> sparrow -> hawk, what role does the oak tree play?[1]

(a)A decomposer

(b)A secondary consumer

(c)A producer

(d)A primary consumer

A4.A garden lizard in Singapore is often seen basking motionless in a sunny, open spot early in the morning. Since lizards cannot generate their own body heat internally, what is the main purpose of this behaviour?[1]

(a)To camouflage itself from predators by staying still

(b)To digest its food more slowly

(c)To attract insects that it can then eat

(d)To absorb heat from the sun and raise its body temperature so it can become active

A5.A cactus growing in the desert has roots that spread out widely just below the soil surface, rather than growing straight down. What advantage does this root system give the plant after a sudden rain shower?[1]

(a)It helps the plant attract more pollinating insects

(b)It can absorb rainwater quickly over a wide area before it evaporates or drains away

(c)It helps the plant photosynthesise faster

(d)It allows the plant to reach deep underground water year-round

A6.A community garden plot planted with beans is watered daily but placed in heavy shade under a large tree. The beans grow poorly. What is the most likely reason?[1]

(a)Water is not needed once carbon dioxide is present

(b)The shade limits the light energy available for photosynthesis

(c)Shade increases the amount of chlorophyll needed

(d)The tree absorbs all the carbon dioxide before it reaches the beans

A7.In a pond food web, algae is eaten by tadpoles and small fish; frogs eat both tadpoles and small fish; herons eat frogs and small fish. If a pollutant kills most of the small fish, what is the most likely effect on the ecosystem?[2]

(a)Tadpoles will begin eating frogs to compensate for the loss

(b)The algae population will decrease because it depends on small fish

(c)Only the herons will be affected, with frogs and algae unchanged

(d)Frogs and herons may decline from losing a food source, while algae may increase from reduced grazing

A8.An astronaut on the Moon drops a hammer and a feather from the same height at the same time, and they land at exactly the same moment, unlike on Earth where the feather would drift down slowly. What is the best explanation, considering both gravity and friction?[2]

(a)Friction is stronger on the Moon, so both objects are slowed equally

(b)The Moon's gravity does not act on light objects like feathers

(c)The Moon has no atmosphere, so there is no air resistance to slow the feather down differently from the hammer, and both fall under gravity alone

(d)The hammer is magnetic and is pulled down faster by the Moon's core

Section B - Short Answer

B1.Name the force that pulls all objects on Earth downwards towards the ground.[1]

B2.A ball is thrown straight up into the air. Explain how its energy changes as it rises to its highest point.[2]

B3.Two species of birds in the same forest both build nests in tree holes and eat the same type of insects. Explain what happens to both bird populations if tree holes and insects become scarce.[2]

B4.Explain how deforestation affects the animals living in a forest.[2]

B5.A toy car is pushed and rolls across a rough table until it stops on its own. A student says the car's energy has disappeared. Explain why this is incorrect, describing what actually happens to its kinetic energy.[2]

B6.A student says, 'The Sun is a producer because it gives plants the energy they need to grow.' Explain why this statement is incorrect.[2]

Section C - Structured

C1.A food web in a pond includes algae, tadpoles, small fish and a heron. Algae are eaten by tadpoles; tadpoles are eaten by small fish; small fish are eaten by the heron.[3]

(a)Identify the producer and ONE consumer in this food web.[2]

(b)State the source of energy for this whole food web.[1]

C2.In a grassland habitat, lions prey on zebras. One year, a disease causes the zebra population to fall sharply.[3]

(a)Explain what is likely to happen to the lion population soon after, and why.[2]

(b)State ONE other organism, besides lions, that is likely to be affected by the fall in the zebra population, and briefly explain why.[1]

C3.Some birds, such as swallows, migrate long distances to a warmer country when winter approaches, while some other animals, such as stick insects, have body shapes and colours that closely resemble twigs or leaves.[4]

(a)State whether migration is a structural or a behavioural adaptation. Explain your answer.[2]

(b)Explain how the stick insect's body shape and colour help it survive.[2]

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