The production possibilities curve represents the maximum combination of goos and services that can be produced with fixed resources and technology, given efficient use of the resources. the combinations of goods and services among which consumers are indifferent. the maximum amount of labor and capital available to society. the maximum rate of growth of capital and labor in a country.

When a person demands something (in economics) they must be , and to buy

What is the name for something that changes the trade-offs that people facewhen making a decision?

Carefully distinguish between economic theory and economic model.  What is the role of value judgments in economic analysis?