What are three types of passive transport? what do these all have in common?

Simple diffusion, osmosis, and facilitated diffusion.

Explanation:

Simple diffusion: It is movement of molecules from an area of higher concentration to an area where lower concentration is present.

Osmosis: It is movement of water with the help of semipermeable membrane depends on its solute concentration, down its concentration gradient.

Facilitated diffusion: It is defined as the diffusion of molecules crossing the plasma membrane takes place with the help of membrane protein such as carrier, and channel proteins.

Passive transport not require any metabolic energy to transport ions. This is the common characteristic of these three passive transport examples.