You are presented with the quiz "What is the name of something some animals use to conserve water and elminate waste?" 

But you don't know the answer, so you turn to your teacher to ask for hints. He says that "some arthropods have special excretory structures" and "terrestrial arthropods have an excretory system that conserves water and eliminates waste". 

So, what's the best answer to the question?


 

      excretory structures     