The mississippi river is a physical feature as it was discovered during a time where man weren`t capable of such construction in the earth.
Isostatic rebound occurs when a load is imposed on or removed from the lithosphere. The surface tends to rise or sink as the lithosphere rises or sinks in the asthenosphere. Loads may consist of large lakes, oceans (on continental shelves during eustatic sea level rise), ice, sediment, thrust sheets, and volcanoes.
Deposition is the geological process in which sediments, soil and rocks are added to a landform or land mass. Wind, ice, water, and gravity transport previously weathered surface material, which, at the loss of enough kinetic energy in the fluid, is deposited, building up layers of sediment.
The vast pollution which occurs globally can have a significant impact on air quality on a local scale. The reason for this is quite simple: polluted air can easily get trapped beneath a cloud cover, or be literally "blown" away to other locations, and when much polluted air gets accumulated, it can have devastating heath effects on a local population, not just to humans, but to animals and plants as well. Overall, the vast global pollution can effect the smallest of regions on an unprecedented scale.
