Why did the soldiers trains for months the invasion

Soldiers trained rigorously before the D-Day invasion. This was a one shot opportunity that would be extremely hard to duplicate. They had to be on point, prepared and ready to do whatever it takes. Training increases your chances of surviving and completing your assignment as best as possible. So in order to be in their best shape, they trained for months to prepare for that invasion.

studies show tha in 7.5 billion years from now, the expanding sun will engulf, and destroy, the earth.