In a Teleost Fish,water Enters the Mouth When The

Question

In a teleost fish,water enters the mouth when the
A)operculum closes.
B)buccal cavity expands.
C)opercular cavity expands.
D)gills contract.

Accepted Answer

Water enters the mouth of a teleost fish when the buccal cavity expands. The buccal cavity is a muscular chamber that expands to create a negative pressure, which draws water into the mouth and over the gills for gas exchange. The operculum and opercular cavity are not directly involved in the process of water intake. The gills are responsible for extracting oxygen from the water that passes over them but do not play a role in actively bringing water into the fish's mouth.