Question

During gastrulation the dorsal lip of blastopore (1 external sign of gastrulation) appears
A) Anteriorly in the pigmented area of egg
B) Posteriorly in the yolky cytoplasmic area
C) In the centre of the egg
D) Behind the grey crescent area

Answer 1

During gastrulation, the dorsal lip of blastopore appears behind the grey crescent area. 

So D is the correct answer

I hope it will help you
regards

Answer 2

During gastrulation the dorsal lip of blastopore (1 external sign of gastrulation) appears Behind the grey crescent area