From an overall perspective, A would be the best answer. Since the Nile River has always been one of the biggest rivers in history, it would most likely sustain life for the people. As well as the mediterranean, people for thousands of years relied on the Mediterranean Sea for their food and even their transportation.
Grain farming is done for economic activity and this makes it commercial. It is highly specialized and mechanised. The yield per acre is low so the farms are big. The yield is high per man so little manpower is needed for production. Grain farming is subject to market conditions like climate.
Carbonate rocks, like limestone <span><span>dolomite's, and chalk on earth</span> </span>
because the bottom of the ocean is basically unreachable without the right equipment.
