progesterone since it is what prepares and sustains the uterus for the fetus
The uterus keeps the trachea from collapsing in a fetal pig.
Amniotic fluid
she hates you
gravity
There is no requirement that they ever do it. The body keeps itself clean.
Sand worms.
the shell keeps the egg from drying out by that I mean it keeps it moist or by leaving it it a wet dry area
He guards the Gates of Hades and keeps the ghosts of the dead from leaving the Underworld.
It keeps the hot air from leaving your house.
Possibly "Fragile"
It could mean that he is scared to loose you..
because the incubator keeps the baby in a temperature like the temperature that the baby had in the womans amnion fluid!(uterus)