Psle 2012 Science Questions And Answers -

A cheek cell and an onion cell are observed.

C) Cell wall Explanation: Plant cells have a rigid cell wall outside the cell membrane for support; animal cells do not.

A student looks at a pencil in a glass of water. The pencil appears broken at the water surface.

(a) Converted to heat and sound energy. (b) Kinetic energy. psle 2012 science questions and answers

(a) How does the thick stem help the cactus survive? (b) Why are there spines instead of broad leaves?

(a) Name this phenomenon. (b) What causes it?

(a) Small intestine. (b) Absorbs water and minerals; stores undigested waste. A cheek cell and an onion cell are observed

A mango seed is planted in a pot with soil. It is watered regularly but kept in a dark cupboard. After 2 weeks, the seed sprouts but has yellow leaves.

(a) Cell wall (or large vacuole or chloroplasts – but onion cells have no chloroplasts; cell wall is best). (b) Controls cell activities / contains genetic material.

A pupil wants to test if light is needed for photosynthesis. She uses two potted plants, one in sunlight and one in a dark cupboard. After 48 hours, she tests both leaves for starch. The pencil appears broken at the water surface

Two identical bar magnets are placed on a table. When the north pole of magnet X is brought near magnet Y, magnet Y moves away.

Water from a pond dries up after a few hot days.

The diagram shows a food web: Grass → Grasshopper → Frog → Snake → Eagle

(a) In which circuit will the bulb be brighter? (b) Explain your answer.