What separates an eon into eras?

a) changes in rock layers

b) spieces extinctions (changes in types of organisms)

c) 300 million year chunks

d) types of plants and animals

How did the lifestyles of various prehistoric North American tribes differ?

What was a purpose of the Social Security Act of 1935?

What was the Byzantine empire

The president is managing a war that is not going well. nevertheless, he refuses to withdraw troops, arguing that doing so would waste the billions of dollars spent and thousands of lives lost fighting the war.

What did the British find to export to India to pay for their tea?

What impact did the Erie Canal have on the united states

Which of these major events occurred during the Precambrian time? A. Landmasses were all below water. B. Cyanobacteria filled the water and air with oxygen. C. Trilobites became extinct. D. People lived on Earth.

What was the response of the soviet union and china to the increasing number of american ground forces in vietnam?

The union blockade during civil war lead to

Which was one of the mongol empires major economic accomplishments