O-Level Combined Science — Biology 3

Question 1

Which part of the cell contains genetic information (DNA)?

Accepted Answer

Nucleus

Answer

The nucleus contains the cell's DNA, organised into chromosomes, which carry genetic information for the cell's functions.

Question 2

What is the function of red blood cells?

Accepted Answer

Carry oxygen

Answer

Red blood cells (erythrocytes) contain haemoglobin, which binds to oxygen in the lungs and carries it to body tissues.

Question 3

What is the term for organisms that break down dead organic matter?

Accepted Answer

Decomposers

Answer

Decomposers (such as bacteria and fungi) break down dead organisms and waste materials, recycling nutrients back into the ecosystem.

Question 4

Which vitamin is produced by the skin when exposed to sunlight?

Accepted Answer

Vitamin D

Answer

Vitamin D is synthesised in the skin when it is exposed to ultraviolet B (UVB) radiation from sunlight. It is essential for calcium absorption.

Question 5

What is the name of the process where plants lose water through their leaves?

Accepted Answer

Transpiration

Answer

Transpiration is the process by which plants lose water vapour through their stomata (pores in leaves). It helps draw water up from the roots.

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