Which structure in a mollusk is responsible for secreting the calcium carbonate that forms its shell?

• A. Radula
• B. Foot
• C. Mantle
• D. Gills

Answer: (C)

Verified step by step guidance

1. Understand the anatomy of a mollusk and the functions of its main structures: the radula, foot, mantle, and gills.
2. Recall that the radula is a tongue-like organ used for feeding, primarily scraping or cutting food.
3. Recognize that the foot is a muscular structure used for movement or attachment to surfaces.
4. Identify that the gills are involved in respiration and sometimes in filter-feeding.
5. Focus on the mantle, which is a specialized tissue layer that secretes calcium carbonate to form and maintain the mollusk's shell.