The slow, conical motion of Earth's spin axis, similar to that of a spinning top, with a period of about 26,000 years for one cycle, is called Earth's .

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.