What is a "cell"?

A cell is the basic structural and functional unit that forms the foundation of all living organisms. It is the smallest unit of life capable of carrying out essential processes, such as metabolism, reproduction, and responding to stimuli. Cells have specialized structures and organelles that enable them to perform specific functions, such as the nucleus containing genetic material, mitochondria producing energy, and the cell membrane regulating the exchange of substances. Together, cells make up various tissues, organs, and systems, working harmoniously to maintain the body's structure, function, and overall health.