Which statement best describes the structure of DNA?

The statement regarding DNA being a double helix composed of nucleotide monomers accurately captures the essential structural features of DNA. DNA is characterized by its double helical structure, which consists of two long strands that wind around each other. Each strand is made up of nucleotide units, where each nucleotide is composed of a phosphate group, a sugar (deoxyribose), and a nitrogenous base (adenine, thymine, cytosine, or guanine). This structure allows DNA to store genetic information effectively and maintain stability while enabling replication and transcription processes key to biological functions.

Other structures mentioned, such as a single-stranded circular form, pertain more to certain types of DNA found in prokaryotes or viral genomes but do not represent the general structure of DNA in eukaryotic organisms. Linear and amino acid compositions correspond to proteins rather than DNA, indicating that these choices do not reflect the fundamental architectural characteristics of DNA. Similarly, a globular structure with an outer envelope suggests a description of cellular organelles or certain types of viruses, diverting from the specific structure of DNA itself.