 TCUs vary in enrollment (size), focus (liberal arts, sciences, workforce development/training), location (woodlands, desert, frozen tundra, rural reservation, urban), and student population (predominantly American Indian).Despite their diversity, tribal identity is the core of every TCU, and they all share the mission of tribal self-determination and service to their respective communities.TCUs engage in partnerships with organizations including U.S. Department of the Interior, U.S. Department of Agriculture, U.S. Department of Housing and Urban Development, the National Science Foundation, National Aeronautics and Space Administration, and universities nationwide to support research and education programs that focus on issues such as climate change, sustainable agriculture, water quality, wildlife population dynamics, and diabetes prevention.