Fact 1: Arthropods are the largest phylum of invertebrates.

Fact 2: Invertebrates are animals without a backbone.

Given the two facts above, answer the question "what are arthropods the largest phylum of?" with the following options: 
- Something to move
 - animals without a backbone
 - Earth orbiting the Sun
 - microorganisms
 - absorb light energy
 - converting mass to energy
 - Generating heat
 - remains of prehistoric life


 

  animals without a backbone       