International relations is the study of interactions and relationships between nations. The combination of all states in the world is referred to as the international system. This system is acknowledged because relationships between two countries will necessarily affect the relationships of these states with other states. All international relations affect the global community. The process of making policy decisions regarding other countries or states is referred to as international politics. International relations use theories, as well as multiple levels of policy and analysis, to examine different topics that affect the international system. For example, the topics of international ethics are concerned with examining human rights, ethnic conflict, genocide, and other political and social issues. International law, on the other hand, is related to the international customs, rules, and procedures that states recognize as legitimate. By examining policies, systems in international relations, researchers can determine how to improve the international system.