Moroccans descended from Berbers, Arabs, and Black Africans exactly like the neighboring Maghrebians. The Berbers are the prehistoric populations of Morocco and are related to the wider group of Paleo-Mediterranean peoples. The Afroasiatic family may have originated in the Mesolithic period, perhaps in the context of the Capsian culture.
Epidemiologic triangle model of disease causation. A common model used in public health illustrates the relationships among an agent, a host and the environment. It applies to biological, chemical and physical agents.
Epidemiology of cancer. The epidemiology of cancer is the study of the factors affecting cancer, as a way to infer possible trends and causes. The study of cancer epidemiology uses epidemiological methods to find the cause of cancer and to identify and develop improved treatments. This area of study must contend with problems of lead time bias and length time bias.