Birth Birt h is the act or process of bearing or bringing forth offspring . In mammals, the process is initiated by hormones which cause the muscular walls of the uterus to contract, expelling the fetus at a developmental stage when it is ready to feed and breathe. In some species the offspring is precocial and can move around almost immediately after birth but in others it is altricial and completely dependent on parenting. In marsupials , the fetus is born at a very immature stage after a short gestational period and develops further in its mother's wombs pouch . It is not only humans and mammals that give birth. Some reptiles, amphibians, fish and invertebrates carry their developing young inside them. Some of these are ovoviviparous , with the eggs being hatched inside the mother's body, and others are viviparous , with the embryo developing inside her body, as in mammals. IF ...
"Dead" and "Dying" redirect here. For the coloring process, see Dyeing . For other uses, see Dead (disambiguation) and Death (disambiguation) . Allegory of death: skeleton holding banderolle "Vigilate quia nescitis diem ...", anon., possibly Dutch or German. Made c.1600 Death is the cessation of all biological functions that sustain a living organism . Phenomena which commonly bring about death include senescence , predation , malnutrition , disease , suicide , homicide , starvation , dehydration , and accidents or trauma resulting in terminal injury . In most cases, bodies of living organisms begin to decompose shortly after death. Death – particularly the death of humans – has commonly been considered a sad or unpleasant occasion, due to the affection for the being that has died and the termina...