How can only four bases in RNA carry instructions for 20 different amino acids?
An amino acid is coded for by a set of three RNA bases. Now there are four different types of RNA bases. Now the total number of different three base sets made from four different bases is 4 x 4 x 4 = 64. These are called codons. Hopefully you can see how 64 codons can easily produce since 20 amino acids since you only need one codon per amino acid. Some amino acids are produced by several different codons and some codons code for other random stuff like stopping and starting DNA translation.
