A valley formed by flowing water, called fluvial valley or river valley, is usually V-shaped. The exact shape will depend on the characteristics of the stream flowing through it. Rivers with steep gradients, as in mountain ranges, produce steep walls and a bottom.
Answers: 1 major earthquakes 2 major volcano eruptions
Explanation: this is also a multiple merge in one which means the center of the earth is overheated causes the layers of the Earth to rotate against each other with Escalades the heat to elevate upward through the tunnels that's up to the volcano causing the volcano to erupt for example the Grand Canyon and other valleys and lakes Got Started from the same volcano earthquake and volcano eruption there are other places in the world has the same Lining Pointe.
I would have to go with Sewage mostly because it smells and because it can really hurt the environment. Plants can die and it just is gross to smell. So this would definitely pollute the earth. I hope this helped! :D
