Fact 1: Adult sponges are sessile.

Fact 2: Sessile Attached permanently, immobile.

Given the two facts above, answer the question "What is true of all adult sponges?" with the following options: 
- they are immobile.
 - at or near the margins
 - They may not survive.
 - water conservation
 - Light passing through water
 - competition
 - To keep their body heat.
 - permineralization


 

 they are immobile.        