Question

The major evolutionary split of protostome animals was based on the _____.

a. nature of the body cavity.
b. presence or degree of segmentation.
c. the number of germ layers present in embryonic development.
d. method of feeding
e. way that the organism grows

Answer 1

e. way that the organism grows

Step-by-step explanation:

During the evolution of animals, there was a great increase in body complexity, emerging specialized organ systems and differentiated structures, which also contributed to the classification of animals.

The protostomies differ mainly in that the blastopore (opening that forms at the stage of the gastrula during embryonic development) will give rise to the embryo's mouth, and the anus will open posteriorly (In deuterostomies, the anus opens first, and the mouth opens later).

Some examples of protostomies are worms, mollusks and arthropods.