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on trending
#carry
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Butter ko peeche chod Diya
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#carry on fire
Answers
Answer:
Prehistory, also known as pre-literary history,[1] is the period of human history between the use of the first stone tools by hominins c. 3.3 million years ago and the invention of writing systems. The use of symbols, marks, and images appears very early among humans, but the earliest known writing systems appeared c. 5000 years ago and it took thousands of years for writing systems to be widely adopted. In some human cultures, writing systems were not used until the nineteenth century and, in a few, not even until the present. The end of prehistory therefore came at very different dates in different places, and the term is less often used in discussing societies where prehistory ended relatively recently.
Sumer in Mesopotamia, the Indus valley civilization, and ancient Egypt were the first civilizations to develop their own scripts and to keep historical records; this took place already during the early Bronze Age. Neighboring civilizations were the first to follow. Most other civilizations reached the end of prehistory during the Iron Age. The three-age systemof division of prehistory into the Stone Age, followed by the Bronze Age and Iron Age, remains in use for much of Eurasia and North Africa, but is not generally used in those parts of the world where the working of hard metals arrived abruptly from contact with Eurasian cultures, such as Oceania, Australasia, much of Sub-Saharan Africa, and parts of the Americas. With some exceptions in pre-Columbian civilizations in the Americas, these areas did not develop complex writing systems before the arrival of Eurasians, so their prehistory reaches into relatively recent periods; for example, 1788 is usually taken as the end of the prehistory of Australia.
The period when a culture is written about by others, but has not developed its own writing system is often known as the protohistory of the culture. By definition,[2] there are no written records from human prehistory, so dating of prehistoric materials is crucial. Clear techniques for dating were not well-developed until the nineteenth century.[3]
This article is concerned with human prehistory, the time since behaviorally and anatomically modern humans first appeared until the beginning of recorded history. Earlier periods are also called "prehistoric"; there are separate articles for the overall history of the Earth and the history of life before humans.
Plant cell, the basic unit of all plants. Plant cells, like animal cells, are eukaryotic, meaning they have a membrane-bound nucleus and organelles.
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