Question

All organisms contain DNA, and every organism's DNA is made of the same four nucleotides. Which must also be universal?

A. All the biological macromolecules contain C, H, and O
B. Most do not contain nitrogen
C. The category that contains nitrogen
D. None of the above

Answer 1

The universal category in reference to DNA's four nucleotides and their chemical composition is the one that contains nitrogen since all nucleotides in DNA include a nitrogenous base.

Step-by-step explanation:

The student has pointed out that all organisms contain DNA, which is made of the same four nucleotides. Since these four nucleotides in DNA contain the nitrogenous bases adenine (A), guanine (G), cytosine (C), and thymine (T), and the fact that nucleotides are composed of a nitrogen-containing ring structure, it is clear that the presence of nitrogen is universal in the DNA of all organisms. Therefore, the category that must also be universal is the one that contains nitrogen.

Nucleotides, the building blocks of nucleic acids, including DNA and RNA, contain carbon, hydrogen, oxygen, nitrogen, and phosphorus. The presence of nitrogenous bases in every nucleotide explains why nitrogen is a common element in the DNA of all life forms.