How is the public debt calculated? 
a. by adding up consumption, investment, government purchases, and net exports and then cumulating the annual totals over the years of the nation
b. by subtracting consumption and investment from government spending each year and then cumulating the annual totals over the years of the nation
c. by subtracting current government spending from current government tax revenues
d. by adding up the difference between annual government tax revenues and annual government spending and cumulating the differences over the years of the nation

Which of the following businesses is most likely to disrupt an existing industry? a. closer connex developed an earphone that receives emails and text messages and converts them to voice messages. the first models had poor reception, but they rapidly improved over time. b. mega technologies reconfigured the components used in its touchscreen tablets to create a new type of wearable device for use in restaurants and other service industries. c. particle inc. developed a teleportation technology that can transport physical materials instantaneously across great distances. d. altrea added advanced camera technology to its premium line of smartphones so that they would take the highest-quality photos of all phones on the market.