How did the inca empire's policy of mandatory public service contribute to development of its empire?

Why did the united states become involved in the soviet-afghan war? the united states wanted access to the afghan oil fields. the united states wanted to retaliate against the soviet boycott of the 1984 olympics in los angeles. representative charlie wilson convinced congress to fund afghan resistance to soviet influence. president ronald reagan wanted to force the soviets to withdraw from afghanistan.

What from the columbian exchange had perhaps the biggest impact on the world?

Take another look at the population pyramid for france in 1950. notice the disparity between the male and female populations in the 55 to 70 year-old age group. what historical event could account for this disparity?