The _____ is a fluid-filled sac which will eventually surround the fetus. At first the fluid is derived directly from the _____, but by birth much of its volume is _____. It provides cushioning and support, and _____, during development.

3000+ review questions on anatomy and physiology. 

Anatomy refers to the internal and external structures of the body and their physical relationships, whereas physiology refers to the study of the functions of those structures.