12. If a molecule of socium [small, fat-insoluble) needs to get into a cell, but there's already a high concentration of sodium inside the cell compared to outside:
a. To get into the cell, the molecule must move down the concentration gradient
b. For the molecule to get into the cell, energy must be used.
c. The molecule could enter the cell using simple diffusion.
d. The solution outside the cell is isotonic.