Alkanes and alkenes differ in that alkene molecules contain at least one:

A. oxygen atom

B. double bond

C. triple bond

D. chlorine atom

Double bond

Explanation:

an alkene is a unsaturated hydrocarbon which means that it contain at least one double bond

The answer to your question is B. double bond.

Explanation:

Both alkanes and alkenes are hydrocarbons composed by carbon and hydrogen.

The different between these compounds is that alkanes have only single bonds are are represented as: H H

| |

H - C - C - H

| |

H H

Alkenes have at least one double bound in their structure and are represented as

H - C = C - H

| |

H H