Question

diffusion can be described as...
requiring a semipermeable membrane.
a form of transport that requires spending energy.
the movement of molecules from an area of lower concentration to an area of higher concentration.
the movement of molecules from an area of higher concentration to an area of lower concentration.

Explanation:

Diffusion is the passive movement of molecules (no energy required) from an area of higher concentration to an area of lower concentration. Osmosis (requires a semi - permeable membrane) is a special case of diffusion (for water). Active transport requires energy. The first option is about osmosis, the second is about active transport, the third is the opposite of what diffusion is.

Answer:

the movement of molecules from an area of higher concentration to an area of lower concentration.