What is unique about the protein channels which allow molecules to travel by facilitated diffusion?

A. Each channel only allows one type of molecule to pass through it

B. The channel modify the molecules DNA as they pass-through

C. The channels move molecules very quickly

Please help 10 points

A. Each channel only allows one type of molecule to pass through it

Explanation:

Transmembrane proteins from channels spanning the membrane that create hydrophilic tunnels. They only enable diffusion across the protein channel into the cell, for their target molecules.

These are highly specific-they only allow one type or group of related molecules to use the channel. These are types of transmembrane channels, embedded within the membrane, help to maintain selective permeability, while simple diffusion of other small, uncharged molecules can readily occur.