You are presented with the question "What is part of an animal's excretory system?" and the following answer choices: 
- alveoli
 - garbage chute
 - pollen
 - glucose
 - bloodstream
 - kidneys
 - food
 - intake

Now knowing that organs of excretion make up the excretory system and leptospiral organisms cause infection in the kidneys and are excreted in urine, choose the best answer.


 

      kidneys   