Precambrian time, period of time extending from about 4.6 billion years ago (the point at which Earth began to form) to the beginning of the Cambrian Period, 541 million years ago. Precambrian time encompasses the Archean and Proterozoic eons, which are formal geologic intervals that lasted from 4 billion to about 541 million years ago, and the Hadean Eon, which is an informal interval spanning from 4.6 billion to 4 billion years ago. The Precambrian represents more than 80 percent of the total geologic record.
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Urbanization
Explanation: Millions poured into cities for jobs in factories during the industrial era. This rapid urbanization resulted in overpopulation, crowded tenements, strain on city service, health issues etc.
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Austin gathers a militia and, with Mexican soldiers, marched to Nacogdoches to put down the rebellion. Despite the rebellion ending before his army got there, Austin won the confidence of the Mexican government. However, the Mexican government began to become distrustful of the loyalties of their American colonists.Explanation:
C. Societies in New Guinea developed agriculture; those in Australia didn't.
A valley is an elongated low area often running between hills or mountains, which will typically contain a river or stream running from one end to the other. Most valleys are formed by erosion of the land surface by rivers or streams over a very long period of time. Some valleys are formed through erosion by glacial ice. These glaciers may remain present in valleys in high mountain or polar areas. At lower latitudes and altitudes, these glacially formed valleys may have been created or enlarged during ice ages but now are ice-free and occupied by streams or rivers. In desert areas, valleys may be entirely dry or carry a watercourse only rarely. In areas of limestone bedrock, dry valleys may also result from drainage taking place underground rather than at the surface. Rift valleys arise principally from earth movements, rather than erosion. Many different types of valley are described by geographers, using terms that may be global in use or else applied only locally.
