Which animals have amnion

8 авг. г. The amnion is a membranous sac which surrounds and protects the embryo. It is developed in reptiles, birds, and mammals, which are hence. Amniotic eggs are different from the gel coated eggs of amphibians in that they have: 1. semipermeable shells which allows gases to pass in (oxygen) or out . They're all methods which we use to protect ourselves. Protection is a natural need for all living organisms. Birds have nests high up in trees, and some.