EVERYDAY SCIENCE

Detailed explanation-1: -First phylum to have complete digestive tract is phylum Nematoda or Aschelminthes. Nematodes do not have a well developed excretory system but they possess a well developed digestive system from mouth to anus.

Detailed explanation-2: -Unlike the flatworms in which food and waste enter and exit from the same opening, nematodes have a complete digestive system. An animal with a complete digestive system has a mouth at one end, a long tube with specialized parts in the middle, and an anus at the other end.

Detailed explanation-3: -Within the tubular nematode is a tubular digestive tract that extends from the mouth on the anterior end to the anus at the posterior of the worm. This digestive tract is composed of a muscular esophagus that connect to a simple intestine that is composed of a single layer of intestinal epithelial cells.

Detailed explanation-4: -All mammals, like dogs, cats, and humans; reptiles, amphibians, fish, birds, and even insects have complete digestive systems.

Detailed explanation-5: -Updated On: 27-06-2022. Digestive system is first completed I phylum aschelminthes.