What characterizes a saturated hydrocarbon?

A saturated hydrocarbon is characterized by having only single carbon-carbon bonds. This structural feature means that every carbon atom in the molecule is fully saturated with hydrogen atoms—each carbon forms four bonds with other atoms, resulting in the maximum number of hydrogen atoms attached. Thus, in a saturated hydrocarbon, there are no double or triple bonds present, nor rings that could reduce the number of hydrogens that a molecule can accommodate.

The presence of only single bonds in saturated hydrocarbons contrasts sharply with other types of hydrocarbons, such as unsaturated hydrocarbons, which contain one or more carbon-carbon double or triple bonds. This structural characteristic leads to the saturation of the molecule with hydrogen, making these compounds typically more stable and less reactive than their unsaturated counterparts.

In summary, the defining characteristic of saturated hydrocarbons is the absence of double or triple bonds, which is why the correct answer emphasizes the presence of only single bonds between carbon atoms.