Définition : A liquid tissue; its major function is to transport oxygen throughout the body. It also supplies the tissues with nutrients, removes waste products, and contains various components of the immune system defending the body against infection.
Définition : A landform that extends above the surrounding terrain in a limited area. A mountain is generally steeper than a hill, but there is no universally accepted standard definition for the height of a mountain or a hill although a mountain usually has an identifiable summit and a local relief of more than 300m.
Définition : A tundra is a terrestrial biome which includes, across its spatial extent, only low-growing vegetation such as dwarf shrubs, sedges and grasses, mosses, and lichens. Tundra biomes rarely have monthly average temperatures above 10 degrees Celsius and have low evapotranspiration ratios.
