Which of the following correctly applies to a catalyst?
A. They do not actually participate in the chemical reaction and therefore are unchanged at the end of the reaction.
B. They provide an alternate lower energy mechanism by which the reaction proceeds.
C. They must be in the same phase as the reactants in the chemical reaction.
D. Biological catalysts are proteins called substrates.
a) B only b) A and B only c) A and D only d) B and C only