What are the three types of passive transport through the cell surface membrane?

The three types of passive transport through the cell surface membrane are diffusion, facilitated diffusion, and osmosis.

Diffusion is the process by which molecules move from an area of higher concentration to an area of lower concentration without the need for energy. This occurs naturally due to the kinetic energy of the particles, allowing substances like oxygen and carbon dioxide to pass through the lipid bilayer of the membrane easily.

Facilitated diffusion also involves the movement of molecules down their concentration gradient but uses specific protein channels or carriers in the membrane to aid in the transport of larger or polar molecules, such as glucose and ions, which cannot freely cross the lipid bilayer.

Osmosis specifically refers to the movement of water across a semi-permeable membrane from an area of lower solute concentration to an area of higher solute concentration. This process is crucial for maintaining cellular homeostasis, influencing cell shape and function.

The other options contain processes that are not classified as passive transport. Active transport, for instance, requires energy to move substances against their concentration gradient. Endocytosis and exocytosis involve the cell membrane wrapping around substances to bring them in or push them out, which also requires energy and is not considered passive.