Thank you for choosing to read the book, “Biology: Best Self-Teaching Biology Guide for Dummies; Understand the Human Science the Best Way.” This book contains a comprehensive, self-teaching, easy-to-grasp biology lesson and guide. The term “biology” was derived from the Greek words bios, meaning life, and logos, meaning study. Biology is literally the study of life. It is a branch of natural science that includes the anatomy, physiology, morphology, and origin of living organisms. Organisms encompass all living entities that either consist of one cell—like bacteria and protozoa—or multiple cells, such as plants and animals. There are three major branches of biology, each of them based on different life forms: zoology, botany, and microbiology. Biology was established on four foundations of study: cell theory, evolution, gene theory, and homeostasis. Biology covers many more areas of study, which this book seeks to put together in one place, in a way that makes the science easy to follow and understand.