Are poriferans unicellular, multicellular, or colonial?

Question

Also, does anyone know what their skeleton is like, or how they're supported? Another thing, how do they reproduce?

Answer 1

colonial

Answer 2

Colonial, of course.

Their skeletons can be either made of CO3 or SiO2

They reproduce by budding ( asexual ) and sexually by cast sperm into the water currents, where it enters other sponges. They are hermaphrodite, though they do not self.