Rivers can provide water, sometimes food , and transportation.
I believe C is the answer, may be wrong though.
Answer:

Explanation:
The diagonal of a square is x units.
Let the side of a square is s.
Using pythagoras,

The area of the square is,
A = s²
So,

So, the area of a square is
sq units.
I think that the question asks about the time of the War in Bosnia and other parts of Yugoslavia in the first part of the 90s. The Serbian soldiers that committed mass murder of Bosnian population, mostly men, referred to this as "ethnic cleansing" which sounded better than "genocide"
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Sea that is the answer????????????