Question

Is Facilitated diffusion1. movement across the membrane without help or assistance?2. Movement across the membrane through a protein channel?3. Movement across the membrane with the help from a transport protein and energy?

Answer 1

Facilitated diffusion is a type of passive transport where ATP is not needed because molecules follow the concentration gradient, just using specialized channels.

This means 2 is the right option: Movement across the membrane through a protein channel.