Sponges are sessile, mostly marine animals from the phylum Porifera. Until the 18th century, scientists classified them as plants because they demonstrated so little movement. More than 4,500 living species, which reproduce through both sexual and asexual means, have been documented. Sponges are colonial in nature, living in groups that may grow to 5 feet (150 cm) in diameter. In common usage, the term “sponge” refers to what part of this aquatic animal? Discuss
Source: The Free Dictionary