Facilitated diffusion across a biological membrane requires ________ and moves a substance ________ its concentration gradient.
A. energy and transport proteins; down
B. transport proteins; down
C. energy and transport proteins; against
D. transport proteins; against
Answer:B
Facilitated diffusion across a biological membrane requires ________ and moves a substance ________ its concentration gradient.
A. energy and transport proteins; down B. transport proteins; down C. energy and transport proteins; against D. transport proteins; against