उत्तर : 1. "TRUE"
व्याख्या :

Answer: A) TRUE Explanation: Carbon monoxide is one of the major pollutant present in the world. The six most common pollutants include ozone, carbon monoxide, sulfur dioxide, lead, nitrogen oxides, and particulate matter.   Carbon monoxide is a common atmospheric pollutant. It is produced largely in combustion processes like in industries and in vehicles. It is a gas that cannot be seen nor smelled.