Why do astronomers use light years to measure distances in space?

Which of the following is not a challenge to instituting sound global environmental policies? a. most changes are inexpensive and easy to implement. b. elected leaders who support unpopular environmental issues often are not re-elected. c. economic considerations outweigh environmental ones in many societies. d. there is no way to enforce international environmental agreements.

Explain how the movement of tectonic plates causes the development of different landforms and naturak disasters

What processes does carbon cycle through the biosphere?