X would equal 5. (need more characters)
Yes, organic material in soil is more productive.
The answer is D. The question asks how different cultures influenced each other so that rules out options A & B. Option C is about the environment being destroyed, and that really has nothing to do with foreign influence.
A: A command economy<span> is one in which a centralized government controls the means of production. ... There are </span>advantages<span> and disadvantages of </span>command economy<span> structures. </span>Command economy advantages<span> include low levels of inequality and unemployment and the common good replacing profit as the primary incentive of production.</span>
