Substances transported by facilitated diffusion A. must have movements coupled to those of other substances.
B. move passively through specific channels from an area of greater concentration to one of lower concentration.
C. are restricted to only one direction through the membrane.
D. may flow to a region of higher concentration by the expenditure of energy.

I think it is B

Explanation:

hope it is right!

B

Explanation: the def. of diffusion is moving without the usage of energy. this elimates D, and C and A are incorrect. B is the correct answer as the specific channels are facilitating diffusion across the membrane.

please give this brainliest if this helped! :}

meteorologists would compare a new weather map with one 24 h old to see how fast a front is moving.