Which is the greatest agent of erosion?

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.

According to the earth science reference tables, during which geologic time period were the continents of north america,south america, and africa closest together?

In the developed world, describe the changing role of women in agriculture.