[Solved] Mary builds a simple refracting telescope using two lenses of focal length 80 cm and 5.0 cm. The respective diameters are 60 mm and 10 mm. How many degrees wide does the moon appear through the telescope if it appears only 1/2 degree wide with the "naked eye"? Consumers: Individuals or groups that purchase goods and services for personal use. Market System: An economic system where decisions regarding investment, production, and distribution are guided by the price signals created through the forces of supply and demand. Public Good: A public good is a product or service that is non-excludable and non-rivalrous, meaning it can be consumed by anyone without reducing its availability to others. Nonexcludability: A characteristic of public goods where it is not feasible to exclude individuals from using the good or benefiting from it.