Education encompasses both the teaching and learning of knowledge, proper conduct, and technical competency. It thus focuses on the cultivation of skills, trades or professions, as well as mental, moral & aesthetic development. Formal education consists of systematic by professional teachers. This consists of the application of pedagogy and the development of curricula. Educational systems are established to provide education and training, often for children and the young. A curriculum defines what students should know, understand and be able to do as the result of education. A teaching profession delivers teaching which enables learning, and a system of policies, regulations, examinations, structures and funding enables teachers to teach to the best of their abilities. Sometimes educational systems can be used to promote doctrines or ideals as well as knowledge, which is known as social engineering. This can lead to political abuse of the system, particularly in totalitarian states and government.