Answer the following question given this paragraph: 

Passive transport is a way that small molecules or ions move across the cell membrane without input of energy by the cell. The three main kinds of passive transport are diffusion (or simple diffusion), osmosis, and facilitated diffusion. Simple diffusion and osmosis do not involve transport proteins. Facilitated diffusion requires the assistance of proteins.


Q: What term describes a way that small molecules or ions move across the cell membrane without input of energy by the cell?


A:
passive transport