Final answer:
A fall in real GDP from one period to another typically signifies an economic slowdown or recession, and a particularly severe and long downturn would be classified as a depression.
Step-by-step explanation:
When we see that real GDP falls from one period to another, we can conclude that the economy is experiencing a slowdown or contraction. The slowing down and speeding up of GDP growth are part of the business cycle. A significant decline in real GDP is termed a recession, and if this decline is particularly prolonged and severe, it is known as a depression. Historically, the pattern of U.S. real GDP since 1900 has shown consistent long-term growth with periodic declines. Examples include the 1930s Great Depression, the 2008-2009 Great Recession, and the recession brought about by the COVID-19 pandemic in 2020. It's also worth noting that economic recessions are characterized by the economy falling below its potential GDP, while expansion periods might see the economy performing at or above potential GDP levels.