Excerpted from
Excerpted from Cracking the AP Environmental Science Exam, 2012 Edition by Angela Marrow, Tim Ligget, and the Staff of the Princeton Review. Copyright © 2011 by the Princeton Review, Inc. Excerpted by permission of the Princeton Review imprint of the Random House Children's Group, a division of Random House, Inc. All rights reserved. No part of this excerpt may be reproduced or reprinted without permission in writing from the publisher.
