Final answer:
Carbon monoxide is a colorless, odorless gas emitted from combustion processes. It can cause harmful health effects by reducing oxygen delivery to the body's organs and tissues, and at extremely high levels, it can cause death.
Step-by-step explanation:
Carbon monoxide (CO) is a colorless, odorless gas emitted from combustion processes. Nationally and, particularly in urban areas, the majority of CO emissions to ambient air come from mobile sources. CO can cause harmful health effects by reducing oxygen delivery to the body's organs (like the heart and brain) and tissues. At extremely high levels, CO can cause death.