Vaginal sac. Vagina means sheath.
If a membrane-bound sac filled with large molecules of oil is suspended in a beaker of water, water will start to enter the sac. The sac will then swell.
scrotum
scrotum
scrotum
scrotum
First, only males have testicles, but they are suspended , in a sac of skin (Scrotum), between the legs (more specifically between the penis and the anus).
The amniotic sac is the membranous fluid filled bubble in which the developing foetus is suspended in utero.
Sure - even male infants will vary in scrotal size - it the sac does become 'pinched' between the thighs, there is nothing to worry about.
The oil molecules will not mix with the water because they are hydrophobic, causing the oil-filled sac to remain intact. The oil sac will float in the water due to the difference in density between oil and water. Over time, the oil molecules may slowly diffuse out of the sac into the water, depending on the permeability of the membrane.
An amniote is any of a variety of types of vertebrate which have an amnion - the sac in which an embryo is suspended - this includes mammals, birds, and reptiles.
Groin.