What were the cataracts of the Nile River ideal places to locate cities

B- for protection

Explanation:

Cataracts are large rapids in a river, so it provided protection by making sure enemy's cold not sail to them

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a social contract.

"a social contract is an agreement between citizens and their leader where the citizens give up certain freedoms in exchange for protection. the constitution of the united states is an example of a social contract."

increases in demand are shown by a shift to the right in the demand curve. this could be caused by a number of factors, including a rise in income, a rise in the price of a substitute or a fall in the price of a complement.

which the answer is:

b