Answer:
b. they use the same set of nucleotides.
Explanation:
All the organisms use same set of nucleotides to specify an amino acid during translation because genetic code is universal. Genetic code which is a unit of genetic code is made up of various codons which are in turn a sequence of three nucleotides. Some of the examples of codons are AUG, CCG, UCG etc. Same codon specifies a particular amino acid to be incorporated into a peptide chain in all the organisms. For example, AUC specifies isoleucine in all the organisms of this earth including humans, plants, bacteria etc.