I'm not sure if this will help, but Twain was against imperialism. He spoke out against what happened in the Philippines during the Philippine-American War (in which rebels fought against the US for not recognizing them as a republic -- this after the Spanish American War) and was concerned over the direction that the country was taking with those actions. Keith, on the other hand, was a businessman and entrepreneur who eventually created the United Fruit Company. Through his business holdings in Costa Rica and the Central American region, his companies managed to influence a great deal of the local economy. Instead of using armies and soldiers to take over a country, his companies did the same thing -- through the economy -- turning many areas into private preserves that fed his business interests. In that way, he was definitely something of an imperialist.
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.
Answer:
Plants would have naturally grown. The ground would have dried up quickly. It would have gotten too crowded along the river. Farming communities would have taking advantage of the bounty and established habitations around them.
Srry im a day late but i hope this helps everybody else who is having trouble on this question :D