[Campbell Biology P.954] Which of the following statements accurately distinguishes an alime... | Practice Question
Which of the following statements accurately distinguishes an alimentary canal from a gastrovascular cavity?
A: An alimentary canal has two openings (mouth and anus), while a gastrovascular cavity has only one opening that serves as both mouth and anus.
B: Digestion in an alimentary canal is primarily intracellular, whereas in a gastrovascular cavity, it is solely extracellular.
C: Animals with an alimentary canal cannot continuously ingest food, unlike those with a gastrovascular cavity.
D: An alimentary canal lacks specialized compartments for stepwise digestion, which are characteristic of a gastrovascular cavity.
Explanation
The text states that an alimentary canal has two openings, a mouth and an anus, allowing for one-way food flow and specialized compartments. A gastrovascular cavity, as seen in hydra, has only one opening that serves for both ingestion and elimination.