Which of the following statements is true regarding enzymes?

Enzymes are biological catalysts that play a crucial role in speeding up chemical reactions in living organisms. One of their key characteristics is that they can be reused multiple times in various reactions. This means that an enzyme can assist in converting substrates into products without being permanently altered or consumed in the process. After catalyzing a reaction, the enzyme remains intact and available to catalyze additional reactions, which significantly increases the efficiency of biological processes.

In the context of the other options, they either misrepresent enzyme functionality or present inaccuracies about their nature. For instance, enzymes are not consumed in the reactions they catalyze, which is a fundamental feature that distinguishes them from reactants. They also do not function at all temperatures; each enzyme has an optimal temperature range within which it operates most effectively. Furthermore, enzymes are known to lower the activation energy of a reaction rather than increase it, facilitating the reaction to proceed more easily. This unique ability for reuse and the other properties of enzymes are vital for metabolism and various biochemical pathways in living organisms.