In Mexico City, physical processes such as inversion and human activities such as
reliance on cars and trucks contribute to
A unequal distribution of income
B erosion
overcrowding
air pollution

The european union was formally established in

Which year held a congressional election and a presidential election

Good scientists always report their observations and results truthfully. this is especially important when a scientist's results go against previous ideas or predictions. coming up with inventive ways to solve problems or produce new things