Enzymes, such as the one shown in the picture, work by fitting onto the substrate molecule like a lock-and-key action. which statement is true, with regard to the enzyme and the substrate? a) the enzyme weakens chemical bonds in the substrate and catalyzes a change into the product. the enzyme itself remains unchanged. b) the enzyme weakens chemical bonds in the substrate and catalyzes a change into the product. the enzyme is also consumed in the reaction. c) the substrate reacts with the enzyme in the active site to produce a product. the enzyme, though changed, does not become a part of the product. d) the substrate reacts with the enzyme in the active site to produce a product. both the enzyme and the substrate combine and change into a product.