The answer to the missing blank above would be 'the Mongols'. The Mongols invaded Russia around 1300s, which arose to economic downfall and overall negative effect to Russia. Because of this, the Russian princes convened and fought to drive Mongols out of the country.
Two of the major approches to study geography are 1.)Systematic Approach &
2.) Regional Approach.
Rosa parks is the oldest public park in the u.s
