The digestive system process food into usable and unusable materials what happens to the unusable food

The Large and Small intestines take all useful minerals and energy substances from your food. anything leftover is discarded as waste, or feces. 

The large + small intestines take care of all the goodies in the food, like proteins and carbohydrates. Everything that is not absorbed, which is waste, or feces, is filtered through and out of your body by means of going to the bathroom. 

Cis the most source of vitamins

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.