Question

Which one functions as the primary organiser in frogs?
A.Dorsal tip of gastrula
B.Grey crescent
C.Chord Mesoderm of gastrula
D.All of the above

Answer 1

Hint: Frog is an amphibian which can survive on both land and on water.
Frog have both lungs and gills in the process of respiration. When it is on land it uses gills for respiration and when it is in water it uses gills as respiratory organs.

Complete step by step answer:
1. In the primary development of frog the blastocoel plays two major functions in development one is it allows cell migration during the process of gastrulation. And the second one is Prevent the interaction of the premature cells with it.
2.The grey crescent area on the embryo of the frog is further developed into Grey coloured area on the surface of the frog present opposite to the sperm entry area. It is a thick crescent like area near the sperm entry.
3. The grey crescent also marks the dorsal side of the embryo as it is present on the dorsal side so it easily identifies between the sides of the embryo before full development.
4. When the stage of the gastrulation is initiated then the first cells form the dorsal tip of the developing embryo. After maturation these cells convert into pharynx cells.
5.The layer of the cells above the gastural cells are called chordo mesodermal which further develop different mesodermal organs in the frog.
So all of the given cell type function as the primary organizers in the development of the frog

Option D is correct.

Note:
The development takes place in the embryo to make it a mature organism is known as primary development.