Give a brief account of enzymes as biological catalysts

enzymes speed up a reaction but aren't used up during the reaction

Explanation:

a catalyst speeds up a reaction by lowering the amount of energy it takes for the reaction to occur enzymes are described as biological catalysts because they speed up the reaction without being used in the reaction

a "theory" a suggestion that is not 100 % accurate, or a figure. some people say its a theory because they of all the passed theory's about one subject. it depends sometimes theory might be accurate and sometimes they are.

layer 3 is younger than layer 6.