United states of america

The United States of America, more often referred to as the "USA," the "U.S.," the "United States," "America," or simply "the States") is a large country in central and north-western North America.
The Grand CanyonIt has a land area of about 9.6 million sq km(about half the size of Russia and about the same size as China). It also boasts the world's third largest population after China and India, with over 300 million people. It includes both densely-populated cities with sprawling suburbs, and vast, uninhabited and naturally beautiful areas. With its history of mass immigration dating from the 17th century, it is a "melting pot" of cultures from around the world.
Regions

The contiguous U.S. (Lower 48) stretches across the midsection of North America, from the Atlantic Ocean to the Pacific Ocean and from the southern borders of Canada to the northern frontier with Mexico and the Gulf of Mexico. Alaska, separated from the continental states by Canadian territory, borders both Canada and Russia (maritime border) in the far northwest. Hawaii is located in the middle of the Pacific, and the unincorporated Caribbean territory (the Commonwealth of Puerto Rico) is found in the region' southeast near the Dominican Republic and Haiti. The United States is composed of 50 states, as well as the city of Washington D.C., a federal district and the nation's capitol. Its many geographic regions are varied. Below is a rough grouping of the country into regions, from the Atlantic to the Pacific..........

African continent

ABOUT AFRICA

Africa is the world's second-largest and second most-populous continent, after Asia. At about 30.2 million km² (11.7 million sq mi) including adjacent islands, it covers 6% of the Earth's total surface area and 20.4% of the total land area.[2] With about 922 million people (as of 2005)[3] in 61 territories, it accounts for about 14.2% of the world's human population. The continent is surrounded by the Mediterranean Sea to the north, the Suez Canal and the Red Sea to the northeast, the Indian Ocean to the southeast, and the Atlantic Ocean to the west. There are 46 countries including Madagascar, and 53 including all the island groups.

Africa, particularly central eastern Africa, is widely regarded within the scientific community to be the origin of humans and the Hominidae tree (great apes), as evidenced by the discovery of the earliest hominids and their possible ancestors, as well as later ones that have been dated to around seven million years ago – including Sahelanthropus tchadensis, Australopithecus africanus, A. afarensis, Homo erectus, H. habilis and H. ergaster – with the earliest Homo sapiens (human) found in Ethiopia being dated to ca. 200,000 years ago.[4]

Africa straddles the equator and encompasses numerous climate areas; it is the only continent to stretch from the northern temperate to southern temperate zones.[5] Because of the lack of natural regular precipitation and irrigation as well as glaciers or mountain aquifer systems, there is no natural moderating effect on the climate except near the coasts