Biology

The correct answer is: C.Small and nonpolar

Molecules that are small and nonpolar can easily pass through the cell membrane via diffusion. The lipid bilayer of the cell membrane is composed of hydrophobic (nonpolar) tails, which allows nonpolar molecules to diffuse directly through the membrane without the need for transport proteins or energy. Small size also helps because it allows the molecules to pass through the pores in the membrane more easily.

In contrast:...