A business cycle is: C. a very deep and prolonged economic downturn. C. a period in which output and employment are rising. C. a period in which output and employment are falling. O. a shortrun alternation between economic upturns and downturns. An open economy is an economy: (:3. that trades goods and seryices with other countries. 0 that does not regulate its industries. 0. that does not impose taxes on its citizens. O. in which freedom of speech and religion can be practiced freely