<unk>  is a natural organic compound originally obtained for commercial purposes primarily from shark liver oil, though there are botanic sources as well, including amaranth seed, rice bran, wheat germ, and olives.  All higher organisms produce<unk> , including humans. It is a hydrocarbon and a triterpene.
Squalene
Methylene diphenyl diisocyanate
Dimethyl sulfide
Vinyl ether
Benzene
Mequinol
Toluene diisocyanate
Nitrosamine