Grassland is any area of the Earth whose predominant type of vegetation consists of grasses, rainfall being generally insufficient to support higher plant forms. There are three main types: savanna, or tropical grassland, has coarse grass growing 1m to 4m high, occasional clumps of trees and some shrubs; it is found in parts of Africa and South America. Prairie has tall, deep-rooted grasses and is found in Middle and North America, Argentina, the Ukraine, South Africa and northern Australia. Steppes have short grasses and are found mainly in Central Asia. Grasslands are of great economic importance as they provide food for domestic animals and often excellent cropland for cultivation.