Why did early farmers use slash-and-burn agriculture?
a. to get rid of pests
b. to get rid of old crops
c. to keep the soil fertile
d. to keep undergrowth from drying out the earth

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.