You are presented with the question "what lack respiratory and excretory systems?" and the following answer choices: 
- fish
 - graptolites
 - starfish
 - waste
 - humans
 - barnacles
 - insects
 - ferns

Now knowing that echinoderms lack respiratory and excretory systems and starfish and sea urchins are also echinoderms, choose the best answer.


 

   starfish      