Your answer would be Why are Sea Lampreys a problem in the Great Lakes?
In the text, it explains the answer for this question. For the other three questions, it's asking for a factor of the paragraph rather than the whole thing. The whole paragraph explains the answers for all of the questions, so it's best to ask why are they causing problems.
Oxygen and nitrogen are very electronegative than any other element in the periodic table hence they have more tendency to attract an electron towards itself
