Question

In kidney cells, charged ions like sodium and chloride are reabsorbed from the urine against a concentration gradient. which mode of cellular transport is employed here?

a. facilitated diffusion

b. simple diffusion

c. osmosis

d. active transport

Answer 1

Against their concentration gradient means its active transport.
Diffusion is with the concentration gradient.
Osmosis is the movement of water.

Answer 2

D active transport hope it helps