Deoxygenated blood travels away from the heart and toward the
where it becomes oxygenated.

Do you have an a b c d ? ? respond ; )

Smoking damages the respiratory system by inhalation of a foreign substance, that is absorbed and residue is left behind on our lungs sponge like substance. the gas that is inhaled also increase your blood pressure and dilates your blood vessels. also the process of inhaling and exhaling the smoke it causes irritation to the throat and mouth. smoking can cause lung cancer and other respiratory and circulatory diseases. 

Pe.dometer would be the most useful to you for monitoring heart rate.

Don't pollution air circulation. wasting pollutionclean in your surroundings