Which of the following is a characteristic feature of alkanes in organic chemistry?

• A. They contain a benzene ring structure.
• B. They contain at least one $\equiv$ triple bond between carbon atoms.
• C. They contain at least one $=$ double bond between carbon atoms.
• D. They contain only $-$ single bonds between carbon atoms.

Answer: (D)

Verified step by step guidance

1. Identify the functional group or structural feature that defines alkanes in organic chemistry.
2. Recall that alkanes are saturated hydrocarbons, meaning they have the maximum number of hydrogen atoms attached to each carbon atom.
3. Understand that alkanes have only single covalent bonds between carbon atoms, which is a key characteristic.
4. Differentiate alkanes from other types of hydrocarbons such as alkenes and alkynes, which contain double and triple bonds, respectively.
5. Conclude that the defining feature of alkanes is the presence of only single bonds between carbon atoms, making them saturated hydrocarbons.