How much of the Earth's atmosphere do scientists believe was made of oxygen 2.3 billion years ago?

A.) 70%

B.) 22%

C.) 1%

D.) 10%

What's the population of the united states?

Why is it often difficult to do business across cultures

How are countries in the European Union linked? (Check all that apply)

Where in Russia can a large amount of coal be found? This resource has been difficult to mine. How might the climate of this region explain why?

A surface manifestation of a mantle plume is a A. hotspot B. shield volcano C. stratovolcano

Plate tectonics and evolution, which are held with a high degree of confidence because of rigorous testing and verification, are examples of: guesses. laws. observations. hypotheses. theories.

What is a current source of tension between India and Pakistan?

Which jet stream affects weather in siberia

Geographers show population change over time by using: A.) population pyramids B.) death rates C.) demography D.) standard of living data

the top of the food chain and threatening the health of future generations