Respuesta :
Answer:
The answer is A.
Explanation:
Diffusion is a net movement of molecules where it travels from a region of high concentration to a region of low concentration down a concentration gradient.
Answer:
a- down their concentration gradient.
explanation
thats just how diffusion works.
it's the movement of particles from a places with higher concentration to a place with a lower concentration. That means it goes down a concentration gradient.