You are presented with the question "Which type of system do most animals without backbones have?" and the following answer choices: 
- sensory neurons
 - Veins and arteries.
 - Nervous system
 - Stereo system
 - Root system
 - to move people
 - Skeletal system
 - insects

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


 

   Nervous system      