Birds are descended from species that laid eggs in water. It could be argued that embryos of birds still develop in water because ________.
A) the shell keeps the embryo from drying out
B) the amnion encases each embryo in water
C) the chorion, allantois, and yolk sac provide embryos with nutrients and waste disposal
D) the amnion protect the embryo in the same way that a seed coat protects plant embryos of flowering plants

Question

Quizplus · Accepted Answer

The amnion encases each embryo in fluid, which serves to protect and cushion the developing bird. This fluid is reminiscent of the water in which the ancestors of birds laid their eggs.

Birds Are Descended from Species That Laid Eggs in Water