Enzymes work by a. adding heat to reactant molecules in solution b. increasing the speed of electrons c. making reactants water-soluble d. lowering the energy needed to break bonds

The correct answer is D. Enzymes work by lowering the energy needed to break bonds.

This is called the activation energy, and enzymes lower the activation energy. Activation energy is the energy required to begin a reaction and enzymes function by decreasing this amount of energy, and thereby allowing reactions to proceed more efficiently within an organism. It is important to recognize that enzymes do not change the amount of energy produced or used by a reaction (making the reaction exothermic or endothermic). Enzymes are typically proteins with specific three-dimensional structures that do not function with varying temperature and pH.

Hope this helps!

i'm assuming that the correct answer is indeed the first one/ "a"..