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 "Arthropods are the what without a backbone?" with the following options: 
- largest phylum
 - graptolites
 - insects
 - largest mammals
 - largest organs
 - solid, liquid, gas
 - animals
 - largest species


 

 largest phylum        