Describe Diploblastic and Triploblastic organisation in animals. 

Explanation

Germ layers are group of cells behaving as a unit during early stage of embryonic development
It differentiate to give rise to all the tissues/organs of the fully formed individuals.
On the basis of germ layers animals are classified as follows.
(1) Diploblastic :
Animals in which the cells are arranged in two embryonic layers, an external ectoderm and an internal endoderm are called diploblastic animals.
In addition an undifferentiated layer mesoglea is present in between the ectoderm and the endoderm e.g. coelenterates.
(2) Triploblastic :
The animals in which the developing embryo has a third germinal layer mesoderm, in between the ectoderm and endoderm are called triploblastic animals (e.g. All animals from phylum Platyhelminthes to phylum chordates.