Biology

The correct answer is: B.Ions and large polar molecules

Ions and large polar molecules are least likely to pass through a cell membrane by simple diffusion. This is because the cell membrane's lipid bilayer is hydrophobic, making it difficult for charged particles (ions) and large polar molecules to pass through without assistance from transport proteins. These molecules often require facilitated diffusion or active transport to move across the membrane.

In contrast:

A.Nonpolar molecul...