You are presented with the question "Some deuterostomes lack a centralized what?" and the following answer choices: 
- DNA
 - eardrum
 - critical organs
 - permineralization
 - A ruler
 - nervous system
 - communication center
 - respiratory system

Now knowing that echinoderms lack a centralized nervous system and all echinoderms are deuterostomes , choose the best answer.


 

      nervous system   