What is the gas emitted from vehicles?

Correct answers: (a) Carbon dioxide or (b) Carbon monoxide or (d) Nitrogen oxide

Explanation

Vehicle exhaust contains carbon dioxide, carbon monoxide (from incomplete burning) and oxides of nitrogen, along with unburnt hydrocarbons, sulphur dioxide and particulates.

So more than one option is correct: carbon dioxide, carbon monoxide and nitrogen oxides. Marsh gas (methane) is not a typical exhaust gas.