Answer :
Because your lungs are connected with your internal system, so your lungs help u breathe in/out air for your body, if you don't breathe, than you die than, that's why people die in their sleep because old age, sickness, murder, or even because they didn't have enough air/oxygen In their room to provide them with to help their lungs absorb it. As humans we all die eventually, so that's why you see ads that say ''Don't smoke'' because smoking turns your lungs black and give us really bad health problems so that's why their important because they give us life and air to live.