Answer:
you can miss all 20 if that is what you are asking
Explanation:
The items that can contribute to heart disease is C. Nitrogen oxides and carbon monoxide. These are the chemicals that contribute to pollution. Carbon monoxide is the product from a combustion that can affect our respiratory system whenever we inhale this gaseous chemical. And nitrogen oxides can affect and penetrate areas of the body when inhaled in which our respiratory organs may be affected by diseases because of this chemical.
B. Old Stone Age.........................
