When part of a large, meandering river is cut off from the main river channel, which feature can form? a. an oxbow lake b. a dried-up pond c. a pirated channel d. an abandoned channel

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.