Excerpted from
Excerpted from Cracking the SAT Biology E/M Subject Test, 15th Edition by Judene Wright, M.S., M.A.Ed. and the Staff of The Princeton Review. Copyright © 2014 by TPR Education IP Holdings, LLC. Excerpted by permission of The Princeton Review imprint of the Random House Children's Group, a division of Penguin Random House LLC. All rights reserved. No part of this excerpt may be reproduced or reprinted without permission in writing from the publisher.