The _________ begins to develop about 11 days after conception,and is the sole source of fetal nutrition from the end of week 12 until birth.
A) yolk sac
B) placenta
C) amnion
D) trophoblast
E) blastocyst

Question

Quizplus · Accepted Answer

The placenta begins to develop about 11 days after conception and serves as the sole source of fetal nutrition from the end of week 12 until birth. The yolk sac is responsible for early nourishment of the embryo, but is not the sole source of fetal nutrition. The amnion is a membrane that surrounds and protects the embryo, but is not responsible for fetal nutrition. The trophoblast is a layer of cells that helps form the placenta, but is not the sole source of fetal nutrition. The blastocyst is an early stage of embryonic development, but is not responsible for fetal nutrition.

The _________ Begins to Develop About 11 Days After Conception,and