A sequence of DNA has 120 nucleotides (it is not a complete sequence). How
many amino acids would be in the resulting polypeptide chain?
a. 120 amino acids
b. 240 amino acids
c. 40 amino acids
d. 12 amino acids

40 amino acids would be in the resulting polypeptide chain of a sequence of DNA that has 120 nucleotides.

CODONS:

A codon is a triplet nucleotide sequence in an mRNA molecule that encodes a particular amino acid. Each codon specifies an amino acid. A codon is made up of three nucleotides, whose combination determines the amino acid that is encoded. According to this question, a sequence of DNA has 120 nucleotides. This means that the number of codons that is accommodated in this sequence is 120/3 = 40 codons. Since 1 codon specifies 1 amino acid, therefore, 40 codons will specify 40 amino acids.

Learn more about codons at: link