Answer:
a) Fate of the blastopore
Explanation:
The fate of the blastopore has been used as a character for the classification of animals and the building of taxonomic trees. It is .because this character separatesprotostomes from deuterostomes. In Protostomes the blastopore becomes the mouth and in Deuterostomes the mouth did not come from the blastopore; the blastopore becomes the anus.
Examples of protostomes are the Nematodes, mollusks, annelids etc.
Examples of protostomes are echinoderms and chordates.