The gastrovascular cavity differs from the alimentary canal in that only the gastrovascular cavity

The gastrovascular cavity differs from the alimentary canal in that only the gastrovascular cavity has only a single opening

Explanation:

Both gastro vascular cavity and the alimentary canal are the digestive organs. They both have a sole difference. The gastro vascular cavity is a digestive organ that can be found only in the organisms with one openings like the Jelly fish, flat worms.

But the alimentary canal consists of a mouth in one end and an anus at the end to send away the excretion due to digestion. The alimentary canal is the organ of digestion found in birds, animals, birds. It helps to intake food, digest it, extract the nutrient and supply it to the other parts of the body and send the unwanted digestive products to the excretory system.

answer; i believe its echoic memory,it is believed to last three to four seconds; good luck