The question is in incomplete, so here is the complete question:
Nucleic acids are polymers of just 4 different monomers in a linear arrangement. How many different nucleic acid polymer sequences are possible when the polymer contains 30 monomers?
Polymers are biomolecules formed by monomers. For nucleic acid, like DNA and RNA, as 4 monomers are necessary to "create" 1 polymer, a polymer containing 30 monomers can "produce" 7 different nucleic acid sequences.
