Energy is fundamentally defined as the capacity to perform work, representing a universal physical property that underlies all processes in the physical sciences. It exists in countless forms, including kinetic energy (energy of motion), potential energy (stored energy based on position), thermal energy (related to temperature), and electromagnetic energy. The core principle governing energy transfer is that it cannot be created or destroyed, only transformed from one form to another, a concept formalized by the law of conservation of energy. Biological systems harness and convert different forms of energy, such as converting chemical bond energy derived from metabolic processes into mechanical energy to sustain life functions.