How far back in history do written sources go?

Why is it economically necessary for the east germans to build berlin wall

In a small, closed economy, national income (gdp) is $350 million for the current year. individuals have spent $100 million on the consumption of goods and services. they have paid a total of $60 million in taxes and the government has spent $75 million on goods and services this year. use this information and the national income identity to answer the questions. how much does the economy spend on investment?

After about 1000 b.c, some people in siberia meaning their lives wre bassed on herding animals. a. pastoral b. collective c. irrigate d. dalits