Question

) During the germinal period, the fertilized ovum duplicates and forms a blastocyst. This hollow ball of cells ________.

a. fills the amnion with fluid

b. develops a tail for movement

c. contains the embryonic disk

d. shrinks in size and is absorbed by the blood

Answer 1

C - Contains the embryonic disk

Step-by-step explanation:

After an egg is fertilized, it begins to divide into smaller cells, from the 1 cell stage, to 2, to 4 and so on. Then, on the third day, the cells fall within 16-200 cells and it is then called a morula.

On the fifth day, the morula becomes a ball of calls which is now differentiated into an inner cell mass and a trophectoderm. The inner cell mass becomes the embryo as development goes on and the trophectoderm, becomes the placenta.

As development goes on further, the floor of the amniotic cavity is formed by the embryonic disk, a layer of prismatic cells derived from the inner cell mass.

The embryonic disc develops into 3 layers:

• Endoderm
• Mesoderm
• Ectoderm

There is a major differentiation of cells which gives a template for the origin of development of specific organs of the embryo.