Benzene rings.
Atkinson
Jeffrey K
JK
D001554:Benzene / Q000737:chemistry; D006713:Homogentisic Acid / Q000737:chemistry*; D006801:Humans; D006873:Hydroquinones / Q000737:chemistry*
D006873:Hydroquinones; D001554:Benzene; D006713:Homogentisic Acid