Patella aspera Patella aspera Patella aspera is a species of limpet, a type of sea snail in the family Patellidae. Long considered to be a subspecies of "Patella ulyssiponensis", genetic evidence supports its recognition as a separate species. It is native to Macaronesia. It is known by the common name Azorean limpet, and its local name is "lapa brava". This species lives on rocks in the shallow sublittoral and intertidal zones. It is a keystone species which is of ecological importance as a grazer. It is collected for food. Overharvest is the main threat to the species, which has faced population declines
Human body and about 23 litres of fluid inside cells. The content, acidity and composition of the water inside and outside cells is carefully maintained. The main electrolytes in body water outside cells are sodium and chloride, whereas within cells it is potassium and other phosphates. The body contains trillions of cells, the fundamental unit of life. At maturity, there are roughly 30–37 trillion cells in the body, an estimate arrived at by totalling the cell numbers of all the organs of the body and cell types. The body is also host to about the same number of non-human cells as well