The best answer would be "Using the atomic bomb would change the world forever by making it a more dangerous place."
He supported them because he wanted later to make a treaty with panama to construct the panama canal.
The Contras fought against a group known as the Nicaragua.
Wait for the farmers to finish work before fight practice
A "bad Nile" is a lack of water or too much water, so possible consequences include:
Famine (from crops dying)
Destruction of property (from flood waters)
and much more. However, this type of question normally references something in the text, so I suggest checking that section to see if a specific example was ever given.