Fact 1: Mollusks are invertebrates such as the common snail.

Fact 2: Invertebrates are animals who lack a backbone or spinal column.

Given the two facts above, answer the question "What does an animal like a mollusk lack that many other animals have?" with the following options: 
- sensory neurons
 - Energy.
 - Bodily water
 - kinetic energy
 - alveoli
 - the skin
 - an organism's body
 - spinal column


 

        spinal column 