Fact 1: Arthropods are the largest phylum of invertebrates.

Fact 2: Invertebrates have no backbone.

Given the two facts above, answer the question "What don't arthropods have?" with the following options: 
- barnacles
 - backbone
 - Weight
 - exoskeleton
 - rights
 - meaning
 - Energy
 - Energy.


 

  backbone       