Production possibilities frontiers are usually bowed outward. This is because.

The Economy is currently experiencing growth.  it reflects growth in an economy.

Explanation:

The production possibilities frontier (PPF) is an economic model used to illustrate how people and nations should decide what goods to produce, how much to produce, and for whom they should produce it.

It's a model and a concept that shows the combination of  two goods that can be produced with the given/ available resources. Production Possibilities Frontier are shifted either inward or outward  as the shifts can be driven by changes in the total amount of available factors of production.

So, when there is an outward shift in the PPF  Curve (i.e when it is bowed outward, it clearly means that the economy is growing and all other things remain constant, and when this happens there will be more production so this will cause a shift in the production possibilities curve outward, or to the right.

the answer is a wheel