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

Question

Quizplus · Accepted Answer

The presence of a mantle, which is a specialized tissue that secretes the shell or outer covering of certain organisms, would identify the organism as a bivalve. Crabs, shrimp, and barnacles do not have mantles. A heart, body cavity, and filter-feeding apparatus are not unique to any of the organisms listed.

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