Classic View Psychology Advanced Placement AP Psychology 2 Biological Bases of Behaviour Classic View 2.1 Interaction of Heredity and Environment 2.2 Endocrine System 2.3 Nervous System 2.4 Neural Firing 2.5 Influence of Drugs on Neural Firing 2.6 The Brain 2.7 Tools for Examining Brain Structure and Function 2.8 The Adaptable Brain 2.9 Sleep and Dreaming