Is diffusion a passive or active process?

Diffusion and facilitated diffusion is a passive process.

What is diffusion ?

In insects,inspiration is called a passive process while expiration an active process.Why?

Give the technical terms used for the following: It is the pressure development in tracheavy elements of xylem as a result of metabolic activities of root and considered to be an active process.

Plasma membrane is a lipoproteinous and trilaminar membrane. It regulates the exchange of materials between the cystosol and extra-cellular medium. Give the reasons for the following: (e) Enlist two differences bewteen passive and active transport.

The rate of diffusion of a gas is proportional to