The highest elevations in the united states are located in
a. the sierra nevada.
b. the great plains.
c. the rocky mountains.
d. the coastal regions.

Historians have recently discovered a historical journal published in the early twentieth century. the journal contains facts based on original sources about the downfall of the early byzantium empire. historians consider this long-lost journal to be a breakthrough in their understanding of the byzantium empire. based on this information, the journal is a source.