Practice question

Protostomes constitute major bilaterian division including Lophotrochozoa and Ecdysozoa characterized embryologically by spiral determinate cleavage involving oblique spindles producing quartets of smaller micromeres spirally arranged over larger macromeres, cell fate determined early, so isolated blastomere fails to develop fully. Additional hallmarks include blastopore forming mouth first, schizocoelous coelom arising from mesodermal splitting and ventral nerve cord. Radial cleavage, enterocoelom and blastopore forming anus typify deuterostomes instead of protostomes. 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.