You are presented with the question "What may be caused by an infection or injury of the organs used to breathe air?" and the following answer choices: 
- Toxicity
 - smoking
 - fertilization
 - pneumonia
 - a broken leg
 - oxygenation
 - Dehydration
 - the skin

Now knowing that pneumonia may be caused by an infection or injury of the lungs and mammals breathe air with lungs, choose the best answer.


 

    pneumonia     