You are presented with the question "What largest organ can cause sickness? " and the following answer choices: 
- Heart
 - lungs
 - immune
 - germs
 - mold
 - Skin
 - Liver
 - Stomach

Now knowing that skin is used for breathing air by frogs and an apathetic frog is probably a sick frog, choose the best answer.


 

      Skin   