The genetic code uses a set of three nucleotides called codons to specify each amino acid in a protein sequence. There are 20 standard amino acids that are commonly found in proteins, although there are a few additional amino acids with specialized functions.
Since each codon consists of three nucleotides, and each codon codes for one amino acid, we can calculate the number of base pairs required to code for a specific number of amino acids by multiplying the number of amino acids by three.
In this case, to code for 84 amino acids, we would need 84 amino acids * 3 nucleotides = 252 nucleotides or base pairs.