What is diffusion best described as?

• A. The movement of substances from low to high concentration
• B. The movement of substances from high to low concentration
• C. The circulation of water due to temperature changes
• D. The transfer of energy in living organisms

Answer: (B)

Diffusion is best described as the movement of substances from high to low concentration. This process occurs as molecules naturally move to areas where they are less concentrated, creating a more uniform distribution of particles in a given space. This movement continues until equilibrium is reached, meaning that the concentrations of the substances are balanced throughout the area.

The concept of diffusion is fundamental in various biological processes, such as the exchange of gases in the lungs and the absorption of nutrients in cells. It is driven by concentration gradients, which is the difference in concentration between two regions. When a substance is more concentrated in one area, there is a net movement of its molecules toward areas of lower concentration, facilitating balance and maintaining homeostasis within living organisms and ecosystems.