Living

Living denotes the condition of organisms that exhibit life, a set of characteristic processes that distinguish living systems from inanimate matter. Core properties commonly cited in biology include organization at cellular or higher levels, metabolism, growth, reproduction, responsiveness to stimuli, and the capacity to adapt to changing conditions through evolution.

Living systems range from single cells to complex multicellular organisms and to entire ecosystems. They acquire energy and matter from the environment, transform it through metabolic pathways, and maintain internal conditions (homeostasis). Most life forms on Earth are based on carbon and water and depend on genetic information stored in nucleic acids.

Biological life is traditionally divided into groups such as prokaryotes (bacteria and archaea) and eukaryotes (plants, animals, fungi, protists). Reproduction can be sexual or asexual, and organisms may be autotrophic (photosynthesis or chemosynthesis) or heterotrophic (consuming organic matter). Evolution via natural selection explains diversity and adaptation over time.

Beyond biology, "living" is used in philosophy and everyday language to distinguish active, present life from dead matter and to discuss concepts such as consciousness, personhood, and quality of life. Debates over what constitutes life, the conservation of living systems, and questions of end-of-life care reflect the intersection of science, ethics, and society.