How are viruses similar to parasites?

 Is an organism that lives on or in a host and gets its food from or at the expense of its host. Is a small infectious against that replicates only inside the living cells of other organisms. Parasitesinfect hosts that exist within their same geographical area.

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. 

The lungs are the bags that hold air as it is inhaled oxygen gas that is in the air moved into the blood-and the heart pumps to move this oxygenated blood to cells in the body that need energy