Which of the following is true about alkenes?

Alkenes are characterized by the presence of at least one double bond between carbon atoms. This feature distinguishes them from alkanes, which consist only of single bonds and are saturated with hydrogen atoms, as well as alkynes, which contain triple bonds. The double bond in alkenes contributes to their unique chemical reactivity and is essential for their identification.

Understanding that alkenes possess double bonds also helps clarify why other options do not accurately describe them. For instance, alkenes cannot contain triple bonds, as this would classify them as alkynes instead. The general formula for alkenes is actually CnH2n, contrasting with the formula for alkanes (CnH2n+2), indicating that alkenes are not saturated but rather unsaturated hydrocarbons. Therefore, the assertion that alkenes are saturated hydrocarbons doesn't hold, reinforcing the correctness of the statement about their double bond.