The cell membrane allows which tiny molecules to move freely through it.

Starch is a ... and is ... to pass through.

The cell membrane is said to be...

Diffusion is a ..., it ... require energy.

What is the definition of diffusion?

In diffusion, molecules always move along a concentration gradient from ... to ... concentration.

Diffusion is the means by which useful substances such as ..., enter a cell and waste materials such as ..., leave a cell.