The distribution of particles across space from high concentration to low concentration

This question is asking to state what is being defined. The term defined in the question is called DIFFUSION

Explanation:

Diffusion is the movement of particles/fluids from a region where they are highly concentrated to the region where they are less in concentration across a space. Diffusion is a form of passive transport i.e does not require energy input to occur. This is because the movement occurs down a concentration gradient.

A concentration gradient i.e difference in concentration occurs when there is an uneven amount/concentration of particles in two regions. Hence, movement occurs naturally to the direction where the particles are less concentrated from where they are more concentrated.

an active site is a region that is present on an enzyme where the reactants or the substrate molecules we can say bind and experience a chemical reaction. the substrate is basically a reactant whose concentration is changing and that is converting into a product after binding at the active site of an enzyme

answer; the correct answer is (beta)