What is activation energy ?

Explanation

**Step-by-Step Solution:**

1. **Definition of Activation Energy**: Activation energy is defined as the minimum amount of energy required to initiate a chemical reaction. It is the energy barrier that must be overcome for reactants to be converted into products.

2. **Role of Activation Energy in Reactions**: For a reaction to occur, the reactants must collide with enough energy to break existing bonds and form new ones. This energy requirement is what we refer to as activation energy.

3. **Example of Activation Energy**: A common example of activation energy can be seen in biochemical reactions where enzymes act as catalysts. Enzymes lower the activation energy needed for reactions to occur, thereby speeding up the reaction process.

...