History and prehistory | The Origin of Humans and Human Societies | World History | Khan Academy

Question 1

note

Answer 1

• human beings have been around for about 200,000 years

- earth exist for roughly 4 billion years

Question 2

prehistory

Answer 2

• history that occurred before we had writing
• anthropology (study of present and past humans)
• archaeology (subset of anthropology, past study of humans and human society through remains)
• paleontology (remains and pre-human remains)

Question 3

radiocarbon dating

Answer 3

• can be used for things up to 50,000 years old
• nitrogen-14 becomes carbon-14, carbon-14 decays to carbon-12
• ratio of carbon-14 to carbon-12 can be used to tell how old something is