Answer: DNA is made up of repeating units of building blocks called nucleotides.
Explanation.
Deoxyribonucleic acid(DNA) is a long polymer made up of repeating units building blocks called nucleotides. Nucleotides is the organic building block of DNA and it consist of sub unit molecules, a nitrogenous base called nucleobase, a six carbon sugar called deoxyribose and a phosphate group. The bases use in DNA are adenine(A), cytosine(C), thymine(T) and guanine(G). Nucleotide is important for cellular metabolism.
The hemoglobin molecule has four binding sites for oxygen molecules: the iron atoms in the four heme groups. Thus, each Hb tetramer can bind four oxygen molecules.
