Why do living things use enzymes instead of heat as a source of activation for energy?

Living things use enzymes as catalysts to lower the activation energy required for biochemical reactions, enabling them to proceed at the temperatures compatible with life. Unlike heat, which can denature proteins and harm cellular structures, enzymes are highly specific and operate efficiently under mild conditions. This specificity also allows for precise regulation of metabolic pathways, ensuring that reactions occur in a controlled manner. Overall, enzymes facilitate necessary biological processes without the risks associated with high temperatures.