In a rock 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

Question

Quizplus · Accepted Answer

The presence of a mantle is a characteristic feature of mollusks, which includes bivalves such as clams and mussels. This would allow for the most certain identification of the organism. The other structures listed are present in multiple groups of organisms, making identification more difficult.

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