Practice question

Deuterostomes encompassing Echinodermata, Hemichordata and Chordata display distinctive deuterostomy where blastopore generated by gastrulation invagination persists as anus while mouth perforates secondarily anteriorly from archenteron tip, hence name mouth second. This program associates with radial indeterminate cleavage supporting regulative development where early blastomeres remain totipotent, enterocoelous coelom formation via archenteral pouches and dorsal hollow nerve cord in chordates. Protostomes show opposite blastopore forming mouth, spiral cleavage and schizocoely, making blastopore-to-anus fate primary deuterostome diagnostic criterion. This concept holds high importance for NEET, CBSE board, CUET and competitive examinations focusing on comparative morphology and evolutionary taxonomy within animal and fungal diversity.