Select from the following. +Toxicity; +smoking; +fertilization; +pneumonia; +a broken leg; +oxygenation; +Dehydration; +the skin;
Q: You are presented with the quiz "What may be caused by an infection or injury of the organs used to breathe air?" But you don't know the answer, so you turn to your teacher to ask for hints. He says that "pneumonia may be caused by an infection or injury of the lungs" and "mammals breathe air with lungs". So, what's the best answer to the question?
A:
pneumonia