Final answer:
The production possibilities curve slopes downward and is concave because resources are scarce and there are opportunity costs associated with producing more of one good over another.
Step-by-step explanation:
The downward-sloping production possibilities curve implies that factors of production are scarce because, at any given point, producing more of one good or service necessitates reducing the production of another. This trade-off is due to the limited availability of resources such as labor, land, capital, and raw materials. As such, the curve demonstrates the maximum possible amounts of two commodities that an economy can produce with its existing resources and technology, highlighting the trade-offs and opportunity costs associated with producing different combinations of goods. When an economy uses its resources to increase the production of one good (like snowboards), it must decrease the production of the other good (like skis) because the factors of production are not limitless. This is represented graphically by the fact that the curve slopes downwards. The curve is also concave (or bowed out) to reflect the law of increasing opportunity costs, which states that as the production of one good expands, the opportunity cost of producing additional units of that good increases.