Biology

The correct answer is: A.They are small and nonpolar.

Oxygen (O₂) and carbon dioxide (CO₂) are small, nonpolar molecules, which allows them to easily pass through the lipid bilayer of the cell membrane by simple diffusion. The lipid bilayer is made up of hydrophobic (water-repelling) fatty acid tails, and nonpolar molecules like oxygen and carbon dioxide can pass through this hydrophobic region without the need for transport proteins or energy.

In contrast:

B.They are large and polar is f...