Boundaries between the continents of Earth Boundaries between the continents of Earth The boundaries between the continents of Earth are generally a matter of geographical convention. Several slightly different conventions are in use. The number of continents is most commonly considered seven but may range as low as four when the Americas and Afro-Eurasia are each considered a single continent. According to the definition of a continent in the strict sense, an island cannot be part of any continent, but by convention and in practice most major islands are associated with a continent. There are three overland boundaries subject to definition: While the isthmus between Asia
Largest organisms one of the largest and oldest clonal colonies on Earth. Among animals, the largest species are all marine mammals, specifically whales. The blue whale is believed to be the largest animal to have ever lived. The largest land animal classification is also dominated by mammals, with the African bush elephant being the most massive of these. The largest single-stem tree by wood volume and mass is the giant sequoia ("Sequoiadendron giganteum"), native to Sierra Nevada and California; it typically grows to a height of and in diameter. Multiple-stem trees such as banyan can be enormous. Thimmamma Marrimanu in India spreads