The goal of the AP Environmental Science course is to provide students with the scientific principles, concepts, and methodologies required to understand the interrelationships of the natural world, to identify and analyze environmental problems both natural and human-made, to evaluate the relative risks associated with these problems, and to examine alternative solutions for resolving or preventing them. Environmental science is interdisciplinary; it embraces a wide variety of topics from different areas of study. Yet there are several major unifying themes that cut across the many topics: Science is a process, Energy conversions underlie all ecological processes, The Earth itself is one interconnected system, Humans alter natural systems, Environmental problems have a cultural and social context, and Human survival depends on developing practices that will achieve sustainable systems.