Q. What is the major evolutionary innovation presented by nematodes? What is the benefits of that innovation?
The major evolutionary innovation of nematodes is the complete digestive system, with two openings (anus and mouth).
Since the defecation and the ingestion processes can occur in different extremities of the digestive tube, beings with a complete digestive system have the benefit of ingesting new food while residuals of already eaten food are still inside the body and not yet eliminated.