This was called an "iron curtain." Western powers noticed issues of blame and stepping up armaments, therefore having a negative response.
It is true. This was called the Trail of Tears.
1-3 are correct and 4 is C.
The Union Army was larger, and was able to draw on a far larger population for replacements. The Union Army had better artillery, and was able to manufacture their own artillery. The Union's forces were made up of a far larger percentage of immigrants, and in general had good junior and mid-level officers, and a lot of rather mediocre top level officers