In the united states, how are ethnicities distributed?

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.

The climate in the temperate zone is cold in summers and warm in winters very cold year-round very warm year-round warm in summers and cold in winters

Can someone me? i need to have this done as soon as possible! i'm putting 20 points on this!