Why is sand used in sand replacement method?​

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 largest internal organ in the frog is the

Ozone in the upper atmosphere has been depleted by a. sulfur dioxide. b. chlorofluorocarbons. c. carbon dioxide. d. oxygen.