Question: As development proceeds in deuterostomes. Need Assignment Help? Multiple Choice the mouth appears at or near the blastopore and the second opening forms the anus at a later point. both the mouth and the anus form simultaneously at or near the blastopore. the first opening at or near the blastopore closes up and the second opening becomes both the mouth and anus. the anus appears at or near the blastopore and the second opening forms the mouth at a later point.