Demospongiae
Demospongiae is a class of sponges characterized by their diverse and abundant species, which are found in a wide range of aquatic environments. These sponges are typically composed of a network of collagen fibers and spicules made of silica or spongin. Demospongiae are known for their ability to filter feed, absorbing nutrients from the water through specialized cells called choanocytes. This class of sponges plays a crucial role in marine ecosystems, providing habitat for various marine organisms and helping to maintain water quality through their filter-feeding activities.