Life is a quality that distinguishes matter that has biological processes, such as signaling and self-sustaining processes, from matter that does not. It is defined descriptively by the capacity for homeostasis, organisation, metabolism, growth, adaptation, response to stimuli, and reproduction.

Living things, or organisms, can be explained as open systems. They are always changing, because they exchange materials and information with their environment. They undergo metabolism, maintain homeostasis, possess a capacity to grow, respond to stimuli and reproduce.

Life comprises individuals, living beings, assignable to groups (taxa). Each individual is composed of one or more minimal living units, called cells, and is capable of transformation of carbon -based and other compounds (metabolism), growth, and participation in reproductive acts.

Life is a characteristic of a living organism that distinguishes the latter from a dead organism or a non-living thing, as specifically distinguished by the capacity to grow, metabolize, respond (to stimuli), adapt, and reproduce.