Question

for diffusion to occur, which condition must be met?
a a concentration gradient must exist.
b a hypotonic external environment must exist.
c a hypertonic external environment must exist.
d dynamic equilibrium must exist.

Explanation:

Diffusion is the movement of substances from an area of higher concentration to an area of lower concentration. A concentration gradient, which is a difference in the concentration of a substance across a space, is essential for diffusion to occur. Hypotonic, hypertonic environments and dynamic equilibrium are not the fundamental requirements for diffusion to start.

Answer:

A. A concentration gradient must exist.