Activation energy is Reaction is used to: Overcome repulsion force between colliding molecules, breaking bonds and Merge Valence electrons. So the obvious answer is D all of them
The activation energy in a reaction is the minimum amount of energy required for a chemical reaction to take place. Since all the options are processes in a chemical reaction, D should be the answer.
The interstellar medium (ISM) is the matter and radiation that exists in the space between the star systems in a galaxy. This matter includes gas in ionic, atomic, and molecular form, as well as dust and cosmic rays.
