Question

multiple-choice question enzymes are catalysts because.... they can be used over and over again in a reaction they can be used only once rewatch

Explanation:

Catalysts (including enzymes) are substances that speed up chemical reactions without being consumed in the process. This means they retain their structure and can participate in the same reaction multiple times. The first option states "they can be used over and over again in a reaction", which aligns with the definition of a catalyst. The second option ("they can be used only once") is incorrect because catalysts are not used up in the reaction.

Answer:

A. they can be used over and over again in a reaction