BIOLOGY, Sixth Edition continues to maintain the standard of excellence that has made it one of the leading college biology textbooks throughout the world. Professors and students alike appreciate this book's readability, accuracy, and clear and exciting presentation of biology. Its three unifying themes—transmission of information, evolution of life, and flow of energy through living systems—are integrated throughout the book as a framework for understanding biology. The book's learning aids have always been recognized as outstanding. In this new edition, the authors have focused more on the process of science, emphasizing how the body of scientific knowledge has been derived. The greatly enhanced illustration program features the addition of many new figures designed by award-winning scientific illustrator, Elizabeth Morales.