Which statement best describes how a catalyst can speed up a chemical reaction? a) the catalyst makes lower energy pathways available. b) the catalyst increases the concentration of products. c) the catalyst binds to enzymes to release substrates. d) the catalyst increases the concentration of reactants.

A) The catalyst makes lower energy pathways available.

Explanation:

A catalyst is a substance which speeds up a chemical reaction without itself being used in the reaction. Activation energy is the thresh hold energy which is required to initiate a chemical reaction. In the absence of catalyst, the activation energy is high therefore reactions are slower. But, presence of catalyst lowers the activation energy required to initiate the reaction as a result of which the reaction gets an alternate energy pathway to proceed which is responsible for speeding up the reaction.

b tumor cells have a cell wall instead of a membrane

explanation:

tumor cells different from normal cells because tumor cells have a cell wall instead of a membrane.