Passive transport is the movement of molecules across the cell membrane without requiring an input of cellular energy. identify which of these options are examples of passive transport.
a. do not require cellular energy to allow molecules to pass through the cell membrane.
b. do not require cellular energy because the kinetic energy of the molecules' movement will drive the movement down the concentration gradient.
c. do not require cellular energy because the molecules are small enough to fit through the membrane.
d. All of the above.
e. a and b
f. None of the above.