Use the following information to answer the questions below.
Some viruses can be crystallized and their structures analyzed.One such virus is Desmodium,or yellow mottle virus,which infects beans.This is a member of the tymovirus group and has a single-stranded RNA genome of ~6300 nucleotides.Its virion is 25-30 nm in diameter,and is made up of 180 copies of a single capsid protein that self-associate to form each capsomere,which has icosahedral symmetry with 20 facets.
-If this virus has capsomeres with 20 facets,how many proteins form each one?