Through the process of simple diffusion, materials move across a cell membrane
a.
from an area of higher concentration to an area of lower concentration.
b.
from an area of lower concentration to an area of higher concentration.
c.
between areas of equal concentration.
d.
all of these

The correct answer is A from an area of higher concentration to an area of lower concentration

Explanation:

Diffusion is one of the most important membrane transport process which helps in the transport of small molecules and gases across the plasma membrane from higher concentration region to the region of low concentration until the concentration of the transported molecule becomes equal at both sides.

    As the molecule move along the concentration gradient no external energy is needed to carry out simple diffusion.