What does command economy mean

Which statement describes john tuzo wilson’s contribution to the theory of plate tectonics? he proposed that plates carry parts of the seafloor. he theorized that pieces of earth move for a limited time. he suggested that the asthenosphere is broken into segments. he observed seafloor cracks similar to existing cracks in the continents.

Why are shark population in decline worldwide?

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.