Question

which of the following is the radula made of? chitin cellulose calcium carbonate keratin

Explanation:

The radula is a feeding organ in many mollusks and is made of chitin. Chitin is a tough, semitransparent substance that forms the structural component of the radula. Cellulose is found in plant cell - walls, calcium carbonate is common in shells and exoskeletons in some organisms, and keratin is in hair, nails, etc. in vertebrates.

Answer:

chitin