Question

two protein that have proved useful for taxonomic studies

Answer 1

the and is flavonoids and amino acids

Answer 2

Two protein that have proved useful for taxonomic studies are flavonoid and amino acids.

Flavonoid: Chemical structure of flavonoids consist of a 15-carbon skeleton, with two phenyl rings and a heterocyclic ring. It can also be abbreviated as C6-C3-C6

Amino acids: Amino acids are organic compounds which contain amine and carboxyl functional groups, and  a side chain specific to each amino acid.Carbon, hydrogen and nitrogen are key elements  in addition to some other elements.

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