Fact 1: Adult sponges are sessile.

Fact 2: Sessile Attached permanently, immobile.

Given the two facts above, answer the question "what are immobile?" with the following options: 
- adult sponges
 - gastropod shells
 - clouds
 - h2o
 - critical organs
 - all matter
 - an organism's body
 - humans


 

 adult sponges        