In the Following Flowchart Summarizing Membrane Transport,both Active and Facilitated

Multiple Choice

In the following flowchart summarizing membrane transport,both active and facilitated transports terminate at separate carrier proteins.Which statement explains why the lines do not converge at the same carrier protein?

A) The two processes move items across the membrane in opposite directions; the carriers are positioned on opposite sides of the membrane.
B) During facilitated transport, hydrophobic molecules cross the membrane; hydrophilic molecules require active transport to cross the membrane.
C) Energy is required to drive an active transport carrier protein, whereas a facilitated carrier operates down the concentration gradient and requires no energy input.
D) Active transporters move only ions with net charge, whereas facilitated transporters move only polar or neutral molecules.