Why do national income accountants compare the market value of the total outputs in various years rather than actual physical volumes of production? What problem is posed by any comparison over time of the market values of various total outputs? How is this problem resolved?

Firefighters is a company that manufactures smoke detectors. it runs a newspaper advertisement that reminds people of the need to have a smoke detector on every floor of their house. in the advertisement, the company also asks people to think about this the next time they're in the smoke detector section of a hardware store. according to the information provided here, this is an example of