What encompasses the totality of an organism's chemical reactions?

The totality of an organism's chemical reactions is described by metabolism. Metabolism encompasses all biochemical processes that occur within an organism, allowing it to maintain life. This includes both anabolism, which is the process of building larger molecules from smaller ones, and catabolism, which involves breaking down complex molecules into simpler ones to release energy. Together, these processes help regulate energy flow and material exchange within the organism, making metabolism a comprehensive term for all chemical reactions involved in cellular and physiological functions.

Homeostasis refers to the maintenance of a stable internal environment in an organism, but it does not specifically encompass the entirety of chemical reactions occurring within the body. Thus, while homeostasis is essential for the survival of the organism, it is metabolism that encompasses the complete set of chemical reactions.