Economic models like the are not physical models

What is the relationship between marginal external cost, marginal social cost, and marginal private cost? a. marginal social cost equals marginal private cost plus marginal external cost. b. marginal private cost plus marginal social cost equals marginal external cost. c. marginal social cost plus marginal external cost equals marginal private cost. d. marginal external cost equals marginal private cost minus marginal social cost. marginal external cost a. is expressed in dollars, so it is not an opportunity cost b. is an opportunity cost borne by someone other than the producer c. is equal to two times the marginal private cost d. is a convenient economics concept that is not real

Your dormitory, griffingate, has appointed you central banker of its economy, which deals in the currency of wizcoins. assume that the velocity of wizcoins in griffingate is constant at 10,000 transactions per year. right now, real gdp is 1,000 wizcoins, and there are 2,000 wizcoins in existence.

Why is it easier for new entrants to get involved in radical innovations when compared to incumbent firms? a. unlike incumbent firms, new entrants do not have to face the high entry barriers, initially. b. new entrants are embedded in an innovation ecosystem, while incumbent firms are not. c. unlike incumbent firms, new entrants do not have formal organizational structures and processes. d. incumbent firms do not have the advantages of network effects that new entrants have.