You are presented with the question "What is an example of an animal that lacks a respiratory and excretory system?" and the following answer choices: 
- Dog
 - Human
 - alpacas
 - cacti
 - Starfish
 - Leeuwenhoek
 - Elephants
 - cows

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


 

     Starfish    