This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Forensic Medicine
The outer covering of diatom is made of: NEET 14 
Select and explain. 
A. Magnesium, B. Silica, C. Hydrocarbons, D. None
B: Silica
Answer: B: Silica 
Explanation: Ans. Silica