Final answer:
H2O and sucrose (option C) are molecules that most likely pass through a cell membrane via facilitated diffusion, requiring transport proteins, in contrast to O2 and CO2, which pass through via simple diffusion.
Step-by-step explanation:
The molecules most likely to pass through the membrane by facilitated diffusion are H2O and sucrose (option C). Facilitated diffusion is a type of passive transport that allows substances to move across cell membranes with the help of transport proteins. While small, nonpolar molecules like O2 and CO2 can diffuse directly through the lipid bilayer without assistance, polar molecules like H2O and larger molecules such as sucrose cannot readily cross the hydrophobic core of the plasma membrane.
Therefore, they require transport proteins such as channel proteins or carrier proteins to help them move from an area of high concentration to an area of low concentration. Water can move through aquaporin channels, and sucrose typically requires specific carrier proteins. In contrast, O2 and CO2 can move by simple diffusion without the need for facilitated diffusion.