An economic downturn will come. That's a certainty. What's not certain is exactly when and how bad it will be. Will it be a recession—a depression?

And what are the signs of a downward-trending economy? What types of businesses are exceptions to the rule and actually do well during a downturn? Which businesses are non-cyclical and aren't particularly affected by economic ups and downs?

Finally, and perhaps most important, what can businesses do to stay afloat the next time the economy takes a turn for the worst?

An infographic by GreatBusinessSchools.org, a portal that provides information to students before they commit to a business education, tackles those questions—and others.

To see what history has to teach us about what we can expect from the next economic downturn, check out the infographic: