C. living things respond to stimuli in the environment
I believe i<span>mproving air circulation.
Hope this helps!</span>
<span>it comes and goes through the madreporite - a small valve like structure</span>
Wind is the most common cause of erosion in deserts.
No, this is false!
Renewable resources can be syntesized by humans, or not: some of them can, and some can't. This is not what makes them renewable, instead it's the fact that they will still be present in the nature after usage - they will be replaced (the sun will still shine tomorrow even if we harvest its power).