What does metabolism encompass in living organisms?

Metabolism encompasses all cellular processes that support life because it involves the complete range of biochemical reactions that occur within an organism. This includes both catabolic processes, which break down molecules to produce energy, and anabolic processes, which build up components of cells such as proteins and nucleic acids. These processes are essential for maintaining homeostasis, producing energy, synthesizing necessary compounds, and supporting growth and development.

The other choices are limited in scope. Focusing only on energy supply overlooks the crucial building processes fundamental to life. Similarly, concentrating solely on tissue health or growth neglects the vast array of metabolic activities that sustain all life forms, including respiration, digestion, and regulation of cellular processes. Thus, the correct answer reflects the comprehensive nature of metabolism as it supports every aspect of an organism's life.