Subject: Functions of the coelom?

I am a substitute teacher and I wish to discuss this topoic with the students, 
I have researched using textbooks and online and have found most of my 
information that way. However, I still have a couple of questions. The 
textbook makes a big deal out of this issue of the “ coelom ”. I'm just 
curious what were some of the possible survival advantages for an animal like 
the ancestor of modern nematodes may have gained with the appearance of a 
coelom???  Beyond what the text has to offer, what is it about this coelom 
that has had such a huge  and long lasting effect on animal structure and 
function?

Re: Functions of the coelom?