Final answer:
DNA is a polymer because it is a large molecule composed of many nucleotides, which are repeating subunits. The correct answer to the student's question is D) polymer, as it best describes DNA with its repeating sugar, phosphate, and nucleic acid units.
Step-by-step explanation:
DNA is composed of repeating units known as nucleotides, which consist of three parts: a nitrogenous base, a pentose (five-carbon) sugar, and a phosphate group. These nucleotides link together to form a long chain, or a polynucleotide, which is the structure of DNA. This makes DNA a polymer because it is a large molecule made up of many repeated subunits. The question, therefore, pertains to identifying which term best describes DNA with its repeating subunits of sugars, phosphates, and nucleic acids.
In the context of the student's question, the correct answer would be D) polymer. A polymer is a substance composed of large molecules made up of many repeating units. Since DNA is a chain of nucleotides that repeat throughout its structure, it is indeed a polymer. To clarify, micelles refer to arrangements of lipid molecules, monomers are the single subunits that can be linked to form a polymer, lipids are molecules like fats and oils, and salts are ionic compounds. Hence, the term polymer is the most accurate to describe DNA.