What is the role of enzymes in the human body?

Enzymes play a crucial role in speeding up chemical reactions within the human body. These biological catalysts lower the activation energy required for reactions to occur, allowing metabolic processes to proceed at a rate that supports life. Without enzymes, many vital biochemical reactions would either happen too slowly or not at all, making them essential for processes such as digestion, energy production, and DNA replication. By increasing the speed of these reactions, enzymes help maintain homeostasis and enable the body to respond efficiently to various stimuli and metabolic needs.

The other options, while related to important bodily functions, do not accurately represent the specific role of enzymes. Building muscle tissue involves processes like protein synthesis but is not directly affected by enzymes in the same manner. Similarly, while transporting oxygen in the blood is the primary function of hemoglobin, it does not involve enzymes. Facilitating immune responses involves various components of the immune system that are not specifically enzymes but include cells and other molecules that respond to pathogens.