Continent continent. From this perspective, the edge of the continental shelf is the true edge of the continent, as shorelines vary with changes in sea level. In this sense the islands of Great Britain and Ireland are part of Europe, while Australia and the island of New Guinea together form a continent. As a cultural construct, the concept of a continent may go beyond the continental shelf to include oceanic islands and continental fragments. In this way, Iceland is considered part of Europe and Madagascar part of Africa. Extrapolating the concept to its extreme, some geographers group the Australian continental plate
Smallest organisms on the archaeon "Ignicoccus"; it must be in contact with the host organism to survive. Prasinophyte algae of the genus "Ostreococcus" is the smallest free-living eukaryote. The single cell of an "Ostreococcus" measures only 0.8 μm across. Several species of Myxozoa (obligately parasitic cnidarians) never grow larger than 20 µm. One of the smallest species ("Myxobolus shekel") is no more than 8.5 µm when fully grown. The shell of the nut clam "Condylonucula maya" grows only 0.54 mm long. The smallest water snail (of all snails) is "Ammonicera minortalis" in North America, originally described from Cuba. It measures 0.32 to