If short-run average total costs are rising in the oil tanker industry, it implies that economies of scale exist in that industry

In the circular flow model of an economy, households

A) receive income from buyers of goods and services. B) receive income from the sale of factors in the goods markets. C) pay firms for the use of their factors. D) receive income from producers for the use of factors in the factor markets.

Suppose that for the past two months, you have studied economics one hour a day. You now decide to study economics two hours a day. For the past two months

A) your marginal cost of studying economics for an hour must have exceeded its marginal benefit. B) the marginal cost of studying economics must have fallen. C) your marginal benefit from studying economics an hour must have been greater than its marginal cost. D) the opportunity cost of studying economics must have risen.