The outer covering of diagram is made of -: (A) Magnesium, (B) Silica, (C) Hydrocarbons, (D) None
Answer is B. Reff: The synopsis of forensic medicine & Toxicology 28th edition pg: 195 Cell wall is usually strongly impregnated with silica and contain chlorophyll and diatoms a brown pigment. Diatom secretes hard siliceous outer box like skeleton called frustule. They resist heat and acid