Select all the statements that apply to diffusion. A.
It requires energy to move molecules.

B.
It doesn’t take energy to move molecules in and out.

C.
Molecules move from high to low concentration.

D.
Molecules move from low to high concentration.

B and C

Explanation:

Diffusion happens across the concentration gradient, the gradient goes from high to low concentration. This is natural and requires no energy. The only type of diffusion that requires energy is called active transport, this is when molecules move from low to high.