The graph above shows the progress of a chemical reaction. based on the graph, which of the following is true?
select one: a. reaction a is enzyme-catalyzed, while reaction b is not enzyme-catalyzed. b. reaction a is not enzyme-catalyzed, while reaction b is enzyme-catalyzed. c. reaction a uses cofactors, while reaction b does not use cofactors. d. reaction a does not use cofactors, while reaction b uses cofactors.

b. Reaction A is not enzyme-catalyzed, while reaction B is enzyme-catalyzed

Explanation:

Activation energy is the extra energy that must be supplied to reactants in order to cross the energy barrier and thus convert to products.  It is the difference between the energy of activated complex and energy of reactants.

A catalyst is a substance which increases the rate of a reaction by taking the reaction through a different path which involves lower activation energy and thus more molecules can cross the energy barrier and convert to products.

The catalyst itself does not take part in the chemical reaction and is regenerated as such at the end.