4. Which is a possible event that can cause mass human migration? A. Volcanic eruption
B. Lack of invention
C. Creation of modern tools
D. Increased rainfall

What is the importance of having the us forest service, the bureau of land management, the us fish and wildlife service, and the national park service? to manage land resources for conservation and the development of natural resources to manage land resources for conservation and the development of urban areas to preserve historical landmarks and manage the development of urban areas to preserve historical landmarks and manage the development of rural areas