Why did the indigenous people get sick?

The segments shown below could form a triangle.

What mountain range is located near 60*n and 60*e

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.