The passage mentions that when the competitive environment pushed our ancestors to achieve their productivity potential, they could in turn afford more education. This indicates that the competitive environment plays a role in pushing humanity to achieve its productivity potential, supporting option C as the correct answer. Option A is incorrect because the passage does not state that the competitive environment directly causes the development of complex political systems. Option B is incorrect because the competitive environment is described as a factor that enables, not hinders, the achievement of high levels of education. Option D is incorrect because the competitive environment is related to economic performance through its effect on productivity and education. Therefore, the correct answer is C.