Which of the following structures develops FIRST during the period of the embryo?
A) the neural tube
B) the primitive streak
C) the upper arms
D) the placenta

Question

Quizplus · Accepted Answer

The primitive streak is the first visible sign of gastrulation, where the embryo begins to form distinct cell layers. The neural tube and upper arms develop later during the embryonic period, and the placenta is a maternal organ that develops alongside the embryo.

Which of the Following Structures Develops FIRST During the Period