What is South Africa’s biggest economic challenge

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.

Which area on the map would be most likely to have the most oil exploration in since the start of the 21st century? a) b) c) d) plz me

Read the article about the fraser river, one of the most important rivers in canada. what is the most important species of fish in this river? why are the numbers of these fish declining?