By the third week after conception, a sheet of primitive neural cells has formed:
A) a hollow tube called the neural tube.
B) a cavity called the ventricle.
C) a hollow tube called the stem cell.
D) a cavity called the amniotic sac.

Question

Quizplus · Accepted Answer

By the third week after conception, a sheet of primitive neural cells has formed into a hollow tube called the neural tube, which will eventually form the brain and spinal cord.

By the Third Week After Conception, a Sheet of Primitive