Sponges are similar to other animals in that they are multicellular, heterotrophic, lack cell walls and produce sperm cells. Unlike other animals, they lack true tissues and organs, and have no body symmetry.
The shapes of their bodies are adapted for maximal efficiency of water
flow through the central cavity, where it deposits nutrients, and leaves
through a hole called the osculum. Many sponges have internal skeletons of spongin and/or spicules of calcium carbonate or silicon dioxide. All sponges are sessile
aquatic animals. Although there are freshwater species, the great
majority are marine (salt water) species, ranging from tidal zones to
depths exceeding 8,800 m (5.5 mi).
Thier are 37.2 trillion
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found that animals are composed of cells is Theodor Schwann
found that plants are composed of cells is Matthias Schleiden
looked at cork through a compound microscope is Robert Hooke
declared that all living cells can only come from other living cells called living cells "animalcules" is Rudolph Virchow
