The concept of "exchange" is fundamental to the definition of marketing. what is the best description of exchange?

Power plants that rely on coal increase the amount of sulfur dioxide that dissolves into the air, eventually increasing the acidity of precipitation. the higher acidity of rain and snow can damage forests by making it more difficult for plants to absorb minerals from the soil. the equations below provide information about the market demand and supply of electricity. there is a constant marginal external cost of $25 per unit of electricity.d: qd= 200 – 2ps: qs=p – 10what quantity of electricity satisfies allocative efficiency in this market? a. 60b. 70c. 50d. 43.3