In an experiment, you measure the concentration of a polar molecule inside and outside a cell. You find that the concentration is high and gradually increasing inside the cell. You also measure the ATP concentration inside the cell and find that it is dropping. What is your best hypothesis for the process you are observing?

a) facilitated diffusion
b) passive transport
c) simple diffusion
d) active transport
e) endocytosis

e) endocytosis

Explanation:

Because the ATP concentration inside the cell is dropping, we know that the cell is using energy to transport the polar molecule into the cell. This eliminates a), b) and c) because they all don't require energy, and we know that polar substances have trouble diffusing across membranes because the tails of the phospholipids making up the membrane are hydrophobic and non-polar. We also know that the polar substance concentration is increasing in the cell. Honestly, both d) and e) would work because both require ATP; however, endocytosis is more specific as a hypothesis. Thus, e). :)

b) the inside picture would look at a very high temperature in a very low ph