You are presented with the question "what have more complex nervous systems" and the following answer choices: 
- animals without a backbone
 - the wearing away of rock
 - h2o
 - barks and snarls
 - plants
 - density
 - Veins and arteries.
 - remains of prehistoric life

Now knowing that most invertebrates have a more complex nervous system and invertebrates are animals without a backbone, choose the best answer.


 

 animals without a backbone        