There is evidence that global climate change over the past 100 years has led to an increased warming of Earth because of the greenhouse effect. Describe how the solar radiation that arrives at the equator is redistributed around the Earth through atmospheric circulation.

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.

Choose the correct chronological or of the time periods

1. most of russia lies in a environment. a) alpine b) subarctic c) humid continental d) humid subtropical 2. the highest population density is found in the part of russia a) eastern b) northern c) southern d) western