What time in the past does "prehistoric" refer to?

Which of the following is not a pillar of the nuclear proliferation treaty? nonproliferation reduction of nuclear weapons by 85-90% right to peacefully use nuclear power disarmament

What term is given to the border between the central alps and the southern limestone alps?

People keep spending additional units of a particular resource on a want until their marginal benefit is  decreasing withgreater thanless thannot affected by  their marginal cost.