which topic is commonly used to explain activation energy and how chemical reactions happen?\nreaction…

Brief Explanations:

Collision theory states that for a chemical reaction to occur, reactant particles must collide with sufficient energy (activation energy) and proper orientation. It is used to explain activation energy and the mechanism of chemical reactions. Reaction rate is a measure of how fast a reaction proceeds, velocity - distribution is related to the speeds of particles in a system, and spontaneous reaction refers to a reaction that occurs without external influence, but they do not directly explain activation energy and reaction mechanisms like collision theory.

Answer:

B. collision theory