Two possible explanations for disparities in environmental conditions along the lines of income or race are "selection" and "move-in." "Selection" means that polluting industries make decisions to locate in predominantly low-income or non-white areas. "Move-in" means that people with fewer resources are more likely to move into areas where environmental quality is lower. What do you think of these two explanations? Would views of "environmental injustice" differ depending on which factor is more important?