Biologists generally agree that lifeforms are self-organizing systems regulating the internal environment as to maintain this organized state, metabolism serves to provide energy, and reproduction causes life to continue over a span of multiple generations.
Wanabiolojia kwa ujumla wanakubali kwamba maumbo ya maisha ni mifumo inayojipanga inayodhibiti mazingira ya ndani ili kudumisha hali hii iliyopangwa, kimetaboliki hutoa nishati, na uzazi husababisha maisha kuendelea kwa muda wa vizazi vingi.