變更

雌性[[绿头鸭]]和幼[[鸭]]──繁殖是延续生命的要点]]

=== 概论 ===

虽然没有公认的生命定义，[[科学家]]普遍接受生命的生物特徵是[[有机体]]、[[新陈代谢]]、[[细胞]]生长、[[适应]]性、对[[刺激]]有反应及[[繁殖]]<ref>{{cite web|year=2006 |url=http://www.calacademy.org/exhibits/xtremelife/what_is_life.php |title=Definition of Life |publisher=California Academy of Sciences |accessdate=2007-01-07 |deadurl=yes |archiveurl=https://web.archive.org/web/20070208220940/http://www.calacademy.org/exhibits/xtremelife/what_is_life.php |archivedate=2007-02-08 }}</ref>。生命亦可以被简单视为[[生物]]的特徵状态。