Activation energy is required to start a reaction.
Answer: activation
Step-by-step explanation:
Activation energy is the minimum energy the molecules required in order to collide with each other. Chemical reactions require a particular energy to start its function. The reaction only occurs when the products are more stable than the reactants.
This energy can be in the form of kinetic or potential energy. When the molecules collide, the molecules' kinetic energy used to stretch, sometimes bend and possibly break bonds, causing chemical reactions. Faster the objects move, more the kinetic energy it possesses.