Question

The epiblast (outer germ layer of gastrula) forms the
A.Ectoderm
B.Mesoderm
C.Endoderm
D.None of the above

Answer 1

Hint: In the mammalian embryogenesis process, there is two germ layer epiblast (outmost layer) and the hypoblast (innermost layer). These all are also called a bilaminar disc which further transforms into three germ layers.

Complete answer:
In this particular question, we have found the epiblast(an outer germ layer of gastrula) is formed by the ectoderm. The process of the development of an embryo is called embryogenesis. In mammalian embryogenesis, a series of differentiation and segregation processes are involved in the inner cell mass. Note that the gastrulation process is an embryological process in which implanted blastula forms three germ layers. It occurs three weeks after following the fertilization of the ovum. It is a transformative process whereby a bilaminar disc that is epiblast and hypoblast gets transformed into the trilaminar disc consisting of three germ layers such as ectoderm, mesoderm, and endoderm. The epiblast has formed the ectoderm, whereas the hypoblast has been forming the endoderm. Ectoderm is the outer germ layer that forms by the epiblast layer. Later on, it gets differentiated into the integumentary system, nervous system, and pituitary gland. Mesoderm is the middle germ layer formed in the middle of the epiblast and hypoblast layer. This mesoderm layer later gets differentiated into cardiovascular and reproductive systems and connective tissue. Endoderm is the inner or internal germ layer which is formed by the hypoblast. Later, it gets differentiated into the epithelial layer of the lungs, digestive tract, pancreas, bladder, thyroid, and parathyroid gland. The process of gastrulation and the developmental process of an embryo can vary from organism to organism. According to the above explanation, we can say that the option ‘A’ is the correct answer to this question.

Hence, the correct answer is option (A)

Note: During the embryogenesis, there are two germ layer epiblast and hypoblast which is further transformed into the three germ layers which are ectoderm, mesoderm, and endoderm. Ectoderm is formed by epiblast.