How do substance like CO2 and …

The substances like CO2  and water move in and out of a cell by diffusion 

Diffusion is a physical process in which the substance or molecules move from the region of higher concentration to the region of lower concentration. This process occurs in all three states of matter – gases, liquids, or solids and is found fastest in gases when compared to liquids and solids. 

Diffusion is one of the important process and essential activity in human organs. Listed below are a few examples of the diffusion process in the living system.

• Movement of oxygen and carbon dioxide gas in the lungs. 
• Movement of water, salts, and waste products in the kidneys.
• Movement of calcium from food into cells occurs in the intestines. 
• Movement of the molecules during various metabolic or cellular processes.