At the onset of the embryonic period, the _____ appears. It will eventually become the neural tube.
A) stem cell
B) spinal cord
C) primitive streak
D) placenta

Question

Quizplus · Accepted Answer

The primitive streak appears at the onset of the embryonic period and is the first visible sign of gastrulation, which is the process of the formation of the three germ layers. The neural tube eventually forms from the ectoderm layer that is above the primitive streak. Stem cells are present throughout development and are not specific to the formation of the neural tube. The spinal cord is a specific structure that forms later from the neural tube. The placenta is formed mainly from the trophoblast layer, which is not related to the formation of the neural tube.

At the Onset of the Embryonic Period, the _____ Appears