The theory of theorizes organelles that conduct cellular processes were once prokaryotic cells living inside larger host cells.

significant amounts of nitrogen oxides, carbon monoxide, and other pollution

explanation:

passenger vehicles are a major pollution contributor, producing significant amounts of nitrogen oxides, carbon monoxide, and other pollution. in 2013, transportation contributed more than half of the carbon monoxide and nitrogen oxides, and almost a quarter of the hydrocarbons emitted into our air.

relationships play a major role in a human's emotional and mental wellbeing. healthy relationships with the people around you are even linked to a smaller production of cortisol, a stress hormone.

i am going to guess that it is co2.