Fact 1: Invertebrates are animals that lack a vertebral column, or backbone.

Fact 2: Insects are the most common invertebrates.

Given the two facts above, answer the question "What lack a vertebral column?" with the following options: 
- Conifers
 - vertebrates
 - ferns
 - sharks
 - humans
 - insects
 - cacti
 - fish


 

      insects   