Answer the following question given this paragraph: 

Enzymes are proteins that increase the rate of biochemical reactions. Enzymes aren’t changed or used up in the reactions, so they can be used to speed up the same reaction over and over again. Enzymes are highly specific for certain chemical reactions, so they are very effective. A reaction that would take years to occur without its enzyme might occur in a split second with the enzyme.


Q: What are proteins that increase the rate of biochemical reactions?


A:
enzymes