In a tide pool, a student encounters an organism with a hard outer covering that contains much calcium carbonate, an open circulatory system, and gills. The organism could potentially be a crab, a shrimp, a barnacle, or a bivalve. The presence of which of the following structures would allow for the most certain identification of the organism?
A) a mantle
B) a heart
C) a body cavity
D) a filter-feeding apparatus
E) eyes

Question

Quizplus · Accepted Answer

A mantle is a specialized tissue that lines the interior walls of the shells in mollusks such as bivalves. Since one of the possible organisms listed is a bivalve, the presence of a mantle would allow for certain identification of that organism. None of the other structures listed would differentiate between the other possible organisms.

In a Tide Pool, a Student Encounters an Organism with a Hard