Question

Diffusion occurs when molecules move:

• A. From lower concentration to higher concentration.
• B. From higher concentration to lower concentration through a membrane.
• C. From higher concentration to lower concentration.
• D. When energy is used.

Answer 1

The correct option is C

From higher concentration to lower concentration.

The correct option is C

Explanation of the correct option :

1. Diffusion occurs when molecules (gas, liquid, or solid) moves from higher concentration to lower concentration.
2. Diffusion helps in the movement of substances in and out of the cells.

Explanation of the incorrect option:

Option A: Movement of molecules from lower concentration to higher concentration is active transport.

Option B: Movement of molecules from higher concentration to lower concentration through a membrane is osmosis.

Option D: When energy is used it is active transport because here movement of molecules from lower concentration to higher concentration occurs.

Final answer: Diffusion occurs when molecules move from higher concentration to lower concentration.