Radiolarians secrete glassy exoskeletons made of which of the following?

• A. Cellulose
• B. Silicon dioxide (SiO\(_2\))
• C. Calcium carbonate (CaCO\(_3\))
• D. Chitin

Answer: (B)

Verified step by step guidance

1. Understand the question: Radiolarians are a type of protist known for their intricate and glassy exoskeletons. The question asks about the material that composes these exoskeletons.
2. Review the options provided: The materials listed are cellulose, silicon dioxide (SiO\(_2\)), calcium carbonate (CaCO\(_3\)), and chitin. Each of these is a distinct biological or chemical substance.
3. Recall the biological context: Radiolarians are marine organisms that secrete glassy exoskeletons. Glassy structures are typically associated with silicon dioxide (SiO\(_2\)), a compound known for its transparency and rigidity.
4. Eliminate incorrect options: Cellulose is a carbohydrate found in plant cell walls, chitin is a polysaccharide found in arthropod exoskeletons, and calcium carbonate (CaCO\(_3\)) is commonly found in shells and corals. None of these match the glassy nature of radiolarian exoskeletons.
5. Conclude that the correct material for radiolarian exoskeletons is silicon dioxide (SiO\(_2\)), based on its glass-like properties and its known association with these organisms.