Active and passive transport of solutes across a membrane typically differ in which of the following ways?
a.Active transport is usually down the concentration gradient of the solute, whereas passive transport is always against the concentration gradient of the solute.
b.Active transport always involves the utilization of cellular energy, whereas passive transport does not requires cellular energy.
c.Active transport is always faster than passive transport.
d.Active transport uses protein carriers, whereas passive transport uses carbohydrate carriers.
e.Active transport is used for ions, passive transport is used for uncharged solutes