Explain why the process of mining uranium involved in the use of nuclear energy has the greatest environmental impact of the entire process.

The process of uranium mining generates what is called uranium tailings. These are the waste by products of uranium mining. Tailings contain the radioactive decay products of the uranium atom and these products are quite radioactive. Radioactive particles found in tailings can emit anywhere from twenty to one hundred times as much radiation as the natural levels at natural uranium deposits. These radioactive byproducts can lead to cancer if exposed. 

Aphysical change is one that you can put in and remove like a ham sandwich. the stuff you put in there can be changem its not permanet. a chemical change is on that can't be change thats permanet. like when you make a cake and bake it. you can't get those ingredients back.