What kinds of molecules pass using transport proteins

A channel protein serves as a tunnel across the membrane into the cell. More specifically, channel proteins help molecules across the membrane via passive transport, a process called facilitated diffusion. These channel proteins are responsible for bringing in ions and other small molecules into the cell

is this a psat question, if so do not cheat try your best.

name and explain one of the event that occurs during meiosis that increases the variation in offspring even more than simple reproduction?