Starfish Starfish Starfish or sea stars are star-shaped echinoderms belonging to the class Asteroidea. Common usage frequently finds these names being also applied to ophiuroids, which are correctly referred to as brittle stars or "basket stars". About 1,500 species of starfish occur on the seabed in all the world's oceans, from the tropics to frigid polar waters. They are found from the intertidal zone down to abyssal depths, below the surface. Starfish are marine invertebrates. They typically have a central disc and five arms, though some species have a larger number of arms. The aboral or upper surface may be smooth,
Alternatives to animal testing performed on intact animals, the maintenance of cells in culture normally requires the use of animal-derived serum. Although exact figures are difficult to obtain, some have estimated that one million fetal cows are sacrificed each year to obtain the world's supply of fetal bovine serum, used to grow cultured cells. Skin irritation and skin corrosion refer to localized toxic effects resulting from a topical exposure of the skin to a substance. Human skin equivalent tests can be used to replace animal-based corrosive and irritative studies. EpiDerm from Mattek and EpiSkin and SkinEthic RHE model are derived from human skin cells