Q: Some reactions need extra help to occur quickly. they need another substance called what?


Read this paragraph and choose the correct option from the provided answers:

Some reactions need extra help to occur quickly. They need another substance called a catalyst. A catalyst is a substance that increases the rate of a chemical reaction. A catalyst isn’t a reactant, so it isn’t changed or used up in the reaction. Therefore, it can catalyze many other reactions.

 Choices:

- neurotransmitter

- protein

- hormone

- a catalyst


A:
a catalyst