Enzymes affect the reactions in living cells by changing the

Here is the full sentence: Enzymes affect the reaction in living cells by changing the SPEED OF THE REACTION.

Explanation:

The options attached to the question are given below:

A. Products of the reaction  

B. Speed of the reaction  

C. Temperature of the reaction  

D. pH of the reaction

Enzymes are chemical substances, that affect the rate of biochemical reactions by speeding up the rates at which the reactions occur. Enzymes are found in all living cells and they are formed mostly from proteins. Enzymes speed up the rate of biochemical reaction by lowering the activation energy of the reaction. Each enzymes catalyses only specific reactions and work best under specific conditions.