NCHHSTP Social Determinants of Health. Definitions. The National Center for HIV/AIDS, Viral Hepatitis, STD, and TB Prevention uses the words below to describe health equity and social determinants of health. These words are also used by the World Health Organization and the Department of Health and Human Service's Healthy People 2020.
Scientists have narrowed down several of the most likely causes of mass extinction. Flood basalt events (volcano eruptions), asteroid collisions, and sea level falls are the most likely causes of mass extinctions, though several other known events may also contribute. These include global warming, global cooling, methane eruptions and anoxic eventsâwhen the earth's oceans lose their oxygen.
How extinctions have shaped our planet. Earth has experienced at least 5 mass extinctions where 2/3 or more of existing species disappear forever. The causes vary from global temperature to sea level changes, to volcanic activity and meteor impacts. Credit: Our Changing Planet, Upper Midwest Aerospace Consortium. For more info: http://www.umac.org/ocp/.