Diffusion is important in body fluids, because it tends to

(a) Increase local concentration gradients

(b) Eliminate local concentration gradients

(c) Move substances against concentration gradients

(d) Create concentration gradients

Osmosis always involves:

a. A selectively permeable membrane

b. A difference in solute concentration

c. Diffusion

d. Active transport

e. a, b, and c

A physiologist observes that the concentration of sodium inside a cell is decidedly lower than that outside the cell. She also observes that there is a small leakage of sodium into the cell. What cellular process prevents the sodium concentration gradient from disappearing?

a. Osmosis

b. Diffusion

c. Primary active transport

d. Secondary active transport

Differentiate between primary and secondary active transport processes.