The size of a nucleic acid is typically expressed as the number of which of the following in it?

• A. amino acids
• B. sugar molecules
• C. nucleotides
• D. phosphate groups

Answer: (C)

Verified step by step guidance

1. Understand that nucleic acids, such as DNA and RNA, are polymers made up of repeating units called nucleotides.
2. Recall that each nucleotide consists of three components: a sugar molecule, a phosphate group, and a nitrogenous base.
3. Recognize that the size of a nucleic acid is commonly measured by counting the number of nucleotides it contains, since nucleotides are the fundamental building blocks.
4. Note that amino acids are the building blocks of proteins, not nucleic acids, so they are not used to express nucleic acid size.
5. Conclude that the correct unit for expressing the size of a nucleic acid is the number of nucleotides.