Since Galaxia economy is 10 times larger than myopia‘s, it is fair to assume that the capital stock in Galaxia is larger than in myopia. Given the law of diminishing marginal returns - the notion is that as additional capital is used to produce a good, the increments to output decrease - the marginal return to capital in Galaxia is not greater than myopia.
At their beginning, the Arabs were an incredibly weak and loose collection of cities that could have easily been destroyed by Rome, yet the long peace with Rome led to prosperity, therefore B is the answer.
Even if the Earth population is growing, sparsely populated areas still constitute the biggest part of the world; they are not limited to “pristine” or “virgin” areas and are not also well covered by the category of “rural”
