Final answer:
Organic molecules composed of nucleotides are DNA or RNA. Nucleotides are the building blocks of nucleic acids, such as DNA and RNA.
Step-by-step explanation:
Organic molecules composed of nucleotides are DNA or RNA. Nucleotides are organic compounds that consist of three subunits: phosphate groups, pentose sugar (either deoxyribose or ribose), and nitrogen-containing base (adenine, cytosine, guanine, thymine, or uracil). When nucleotides are assembled, they form nucleic acids, which include DNA and RNA.