When it comes to enzymes, the following statement is true:
b) Enzymes increase the rate of a reaction by lowering the necessary activation energy.
Enzymes are biological catalysts that speed up chemical reactions in living organisms. They do this by providing an alternative reaction pathway with a lower activation energy compared to the uncatalyzed reaction. This means that less energy is required to initiate the reaction, allowing it to proceed more quickly.
The first statement, which claims that enzymes make a reaction more exergonic, is incorrect. While enzymes do speed up reactions, they do not change the overall energy difference between the reactants and products. The third statement is also misleading; enzymes do have an effect on the reaction, as they are essential for facilitating the process and ensuring it occurs at a rate that supports life.