The median age of the world's population was estimated to be 29.7 years in 2014, and is expected to rise to 37.9 years by 2050. According to the World Health Organization, the global average life expectancy is 70.5 years as of 2012, with women living an average of 73 years and men approximately 68 years.
A grassland is an area of land that mostly contains grasses. There are wild grasses, and less trees. Several parts of the world have grasslands. Grasslands are found in Africa, North America, Central Asia, South America, and near the coasts of Australia. The largest grasslands are in East Africa.Grasslands with a few scattered trees are called savannas.Others are called prairies or steppes.everal parts of the world have grasslands. Grasslands are found in Africa, North America, Central Asia, South America, and near the coasts of Australia. The largest grasslands are in East Africa.
Topography is the variety of shapes found on the landscape determined by slopes, elevation and aspects. The topography of grassland ecosystems is a varied landscape of gently rolling hills and prairies, rock outcrops, cliffs, gullies, and low lying areas. Diverse topography is what gives incredible variety to grassland ecosystems. Aspect refers to the direction in which a piece of land is facing. Areas that face towards the south, or the sun, are hotter and drier than areas that face north, or away from the sun. The slope of an area is the angle at which the land lies.