The first principle of economics discussed in chapter 1 is that people face trade-offs. use a production possibilities frontier to illustrate society’s trade-off between two ""goods""—a clean environment and the quantity of industrial output. what do you suppose determines the shape and position of the frontier? show what happens to the frontier if engineers develop a new way of producing electricity that emits fewer pollutants.

The new way to produce electricity will increase the industrial output the enviroment can support. Thus, the PPF will expand as the opportunity cost in clean enviroment decreases

However an enviroment is either clear or not  clean, there isn't more "clean" so it will not expand on the X axis.

Explanation:

The enviroment will decrease at more industrial output.

As we cannot live in an eviroment at zero habiltability we will never shift to complete industrial output.

But, at more insdustrial output we produce, more will it effect the envorement.

b. a single paragraph.

a paragraph is a series of sentences that are organized and make sense, and are all related to a single topic . almost every piece of writing you do that is longer than a few sentences should be organized into paragraphs. this is because paragraphs show a reader where the subdivisions of an essay begin and end, and thus the reader see the organization of the essay into subjects in order to be able to understand its main points.