Nucleosides and nucleotides both contain which of the following components?

• A. 5 carbon sugar and nitrogenous base
• B. 5 carbon sugar, phosphate group, and nitrogenous base
• C. 5 carbon sugar and base
• D. Nitrogenous base and phosphate group

Answer: (A)

The common feature is a pentose sugar attached to a nitrogenous base. That combination—sugar plus base—is present in both nucleosides and nucleotides. Nucleosides are just sugar and base, while nucleotides add one or more phosphate groups to the sugar. Options that mention only phosphate or omit the sugar don’t fit, since the shared component for both molecules is the sugar paired with the base.