Which of the Following Mechanisms of Membrane Transport Is Correctly

Multiple Choice

Which of the following mechanisms of membrane transport is correctly defined?

A) simple diffusion: uses concentration gradient to move highly polar molecules and ions across membranes
B) facilitated diffusion: uses proteins such as ion channels to move substances against their concentration gradient across a membrane
C) primary active transport: uses ATP hydrolysis to move ions against their concentration gradient across a membrane
D) secondary active transport: uses ATP hydrolysis along with an ion gradient to move polar molecules or ions against their concentration gradient across a membrane
E) all of the above