What type of energy is required to start a reaction

Activation energy.
Here’s why:

All chemical reactions, even exothermic reactions, need a certain amount of energy to get started. This energy is called activation energy. For example, activation energy is needed to start a car. Turning the key causes a spark that activates the burning of gasoline in the engine.

   Activation energy is the energy required to start a chemical reaction. Some reactions proceed immediately when the reactants are brought together, but for many others, placing the reactants in close proximity is not enough.

Explanation:

b. He figured out and explained how these changes happened and supported his ideas with evidence

Explanation:

Darwin, through his studies as a naturalist on the voyage of HMS Beagle was able to figure out how evolution occur and explained the changes that happened with several supportive evidence.

During the exploration, Darwin participated in several studies including anatomical, morphological, and paleontologist studies after which he published his books on 'The origin of life'.

In the book, Darwin explained how organism evolve with time and he was able to support his hypotheses with multiple evidence. He later formed the theory of natural selection based on his studies.

The correct option is b.