Question

Which of the following always involves the process of diffusion?
A. The gaseous exchange between the closely placed cells.
B. The movement of water into the cells of living things.
C. The movement of dissolved oxygen from the surrounding water into an amoeba.
D. The movement of carbon dioxide from the air into leaf cells.

• A. Only A and B
• B. Only A and C
• C. Only B and C
• D. Only A, C and D

Answer 1

The correct option is D Only A, C and D

Diffusion is the process of movement of substances, namely liquids and gases from a region of higher concentration to a region of lower concentration.
Among the options listed, in options A, C and D, only diffusion occurs at all times.
Movement of water along the concentration gradient through a membrane (semi-permeable) is called osmosis. In case of option B, we are talking about the movement of water into a living cell in the presence of a semi-permeable membrane. Hence it is an example of osmosis, not diffusion.