The answer to the question is letter A. The term described in the above example or scenario is demand elasticity. The term is a measure of the relavance between a change in the quantity of a particular good and a change of the price of the good.
Answer: Large desert borders
Explanation:
Looking at the map of ancient Egypt, the physical features to the east and west of the nile river is the large desert borders.
This feature helped Egypt in protecting them against their enemies. Most of their enemies them could not sustain journeying long on desert, they were discouraged when it has to do with fighting with the Egyptian's at those areas.
They would kidnap colored people, tie their feet with rope and drag them behind them while tied to a horse(or automobile).