Answer:
The Black Death
I got that question right on Edgenuity.
A trough is a low turning point or a local minimum of a business cycle. The time evolution of many variables of economics exhibit a wave like behaviour with local maxima (peaks) followed by local minima (troughs). A business cycle may be defined as the period between two consecutive peaks.
They defined it in terms of shared language and shared history.
A nation was a place with a single language because languages existed before nations and country names and territory changes but the language stays the same, only evolves as time changes. Shared history is based on the idea that people of a territory and their ancestors share history and are thus bound in a nation.
A paleopathologist studies ancient diseases
