How is the placenta structurally suited to perform its function?

Question

This question always comes up in tests and I'm still unsure of the answer

Answer 1

rich in blood vessels, large open contact area, which suites its function to deliver nutrients and oxygen to the baby from the mother.  Its basically the connection between the mother and her child.

structure and function mentioned specifically here:

http://en.wikipedia.org/wiki/Placenta