Question

small, uncharged substances enter and leave the cell membrane through the process of
a endocytosis
b simple diffusion
c active transport
d facilitated diffusion

Explanation:

Small, uncharged substances cross the cell membrane without energy or proteins via simple diffusion. Endocytosis moves large substances, active transport needs energy, and facilitated diffusion requires proteins—none match the description except simple diffusion.

Answer:

B. simple diffusion.