31. Animals have either no germ layers, two germ layers, or three germ layers. We have learned of some evolutionary adva

[answerhappygod]

31. Animals have either no germ layers, two germ layers, or
three germ layers. We have learned of some evolutionary advantages
provided to species by the structures that develop from these germ
layers. Describe one type of structure that develops from a germ
layer that provides an advantage. What germ layer does it develop
from and how does the function of that structure contribute to
survival, relative to other organisms that do not have this
structure?