This is the backbone of the DNA strand. a. sugar-phosphate groups
b. nucleic acids
c. diploids
d. ribonucleic acids
e. amino acids

B. nucleic acids.

Explanation: A sugar-phosphate backbone (alternating grey-dark grey) joins together nucleotides in a DNA sequence. The sugar-phosphate backbone forms the structural framework of nucleic acids, including DNA and RNA. This backbone is composed of alternating sugar and phosphate groups, and defines directionality of the molecule.  

answer; i believe that the correct answer is (lung);