Question

which statement best explains how enzymes speed up a chemical reaction?
o enzymes remove heat from a chemical reaction
o enzymes lower the activation energy of a chemical reaction
o enzymes add heat to a chemical reaction
o enzymes are not changed as a result of a chemical reaction

Explanation:

Enzymes are biological catalysts. Catalysts speed - up reactions by reducing the activation energy required for the reaction to proceed. Heat addition or removal by enzymes is not their main function in accelerating reactions, and while enzymes are not changed in a reaction (catalytic property), this doesn't explain how they speed up reactions.

Answer:

Enzymes lower the activation energy of a chemical reaction