The amniotic egg is a specialized type of egg found in reptiles, birds, and monotremes (like the platypus). It contains an amnion, which surrounds and protects the developing embryo. This structure allows for the exchange of gases, nutrients, and waste.
Amniotic eggs are different from those of amphibians or fish, which do not have this protective layer.
Pro tip: Understanding these differences can help you appreciate the evolutionary adaptations in egg-laying animals.