Q. What is the coelom? To which structures do coeloms give birth? Are all animals coelomate?
Coeloms are cavities delimited by mesoderm and Coeloms originate the cavities where the internal organs of the body are located such like the peritoneal cavity, the pericardial cavity and the pleural cavity.
Besides coelomate animals there are pseudocoelomate animals, like nematodes and acoelomate animals like platyhelminthes.