Fact 1: Most invertebrates have a more complex nervous system.

Fact 2: Invertebrates are animals without a backbone.

Given the two facts above, answer the question "Most animals without a backbone have what?" with the following options: 
- epidermis and dermis
 - Leptospirosis
 - Veins and arteries.
 - death and devastation
 - scarce resources
 - barks and snarls
 - decreases its bodily water
 - Complex nervous systems


 

        Complex nervous systems 