An organism that lives in or on another organism, often with harmful side effects—but without benefits is a:

If one organism is harming the other while benefiting from the organism they are living in or on then it is a parasite.

Ithink it's d or it can be itger

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.