Question

the movement of oxygen molecules over time from one side of the semipermeable membrane to the other side is known as
a. osmosis.

b. diffusion.

c. plasmolysis.

d. active transport.

Explanation:

• Option A: Osmosis is the movement of water molecules across a semipermeable membrane, not oxygen molecules, so A is incorrect.
• Option B: Diffusion is the movement of particles (like oxygen molecules) from an area of higher concentration to an area of lower concentration across a semipermeable membrane, which matches the described process.
• Option C: Plasmolysis is the shrinking of a cell's protoplast due to water loss in a hypertonic solution, not related to oxygen movement, so C is incorrect.
• Option D: Active transport requires energy and moves substances against the concentration gradient, while oxygen movement here is down the gradient (passive), so D is incorrect.

Answer:

B. diffusion.