Question

Archenteron is cavity in
A) Blastula
B) Gastrula
C) Neurula
D) Morula

Answer 1

Hint: Embryonic development is the development of plants or animals starting from fertilization, then formation of zygote and then development of the zygote into a multicellular embryo.

Complete answer:
During the growth of the zygote into a multicellular organism it undergoes various stages of development such as cleavage, formation of morula, formation of blastula, formation of gastrula, somitogenesis and finally organogenesis.

During these stages different structures or body parts are known to arise that ultimately leads to development of the growing embryo. Archenteron is known as the primary gut that is known to develop during gastrulation giving rise to the digestive tract.

The primary mesenchyme cells detach from the vegetal pole of the gastrula and they enter the blastocoel. The remaining cells then form the vegetal plate as a result of flattening which in turn leads to invagination. The rearrangement of the cells continue till a deeper pouch is formed by the endoderm of the gastrula.

Gastrulation is complete when the endoderm of the archenteron fuses with the ectoderm of the blastocoel wall leading to the formation of a functional digestive tract.

Thus the correct answer is option ‘B’ i.e, ‘Gastrula’.

Note: Formation of the archenteron cavity is a step towards the development of the embryo. The embryo then develops into the fetus and finally to the mature individual. Embryonic development is of importance because it gives us knowledge about the stages of growth of a species before birth which in turn can give an idea of its evolutionary origin.