Question

Digestive tract in ctenophores is
(a) Complete
(b) Incomplete
(c) Both 1 and 2
(d) None

Answer 1

Hint: Ctenophores include a phylum of marine invertebrates. They function as predators. These are free-living marine organisms that do not have a body cavity. An incomplete digestive tract means that the organisms have a single opening that serves as both mouth and anus.

Complete step-by-step answer:
Digestive tract or system is the complete path of food digestion from ingestion to egestion. The complete digestive system is a type of digestive system that has different start and end points. It has two openings, one is the mouth and the other one is an anus. Organs in the digestive system break down food into usable parts for the body. A complete digestive system is more efficient than an incomplete system.
Ctenophores also known as comb jellies belong to marine invertebrates. They have both intracellular and extracellular digestive systems which mean they have a complete digestive system. The breakdown of food materials in intracellular digestion is done into small molecules within the cell. In extracellular digestion, the breakdown of food materials into small molecules occurs outside the cell in the lumen of the alimentary canal.
An incomplete digestive system means that the organisms have a single opening that serves as both mouth and anus. Organisms have the same opening for food and exit for waste. This type of digestive tract is found in Coelenterates and Platyhelminthes.
So, the correct answer is an option (a) Complete

Note: Ctenophores display a wide array of body plans. They are radially symmetrical and diploblastic organisms. They show bioluminescent blue or green and some flashlights eject a bioluminescent "ink" when disturbed. These comb rows scatter light and produce a rainbow effect.