A solute cannot move into a cell by crossing the phospholipid bilayer of the membrane. It can, however, enter through a membrane protein. The fact that solute molecules are entering the cell MOST LIKELY indicates that

(A) energy is being expended by the cell
(B) the solute is moving against its concentration gradient
(C) the solute molecules are hydrophilic
(D) the cell is in a hypotonic solution
(E) solute concentration is higher inside than outside the cell

Which of these BEST describes the part of the molecule shown?

(A) It is hydrophilic.
(B) It forms the outer layer of the plasma membrane.
(C) It is composed of phosphate atoms.
(D) It contains nonpolar covalent bonds.
(E) It is capable of hydrogen bonding.