How did Kerma's location benefit that
kingdom?

The kingdom of Kush prospered because first of all, the Nubians broke away from Egyptian rule and formed an independent kingdom called Kush. Powerful kings ruled the country from its capital at Napata, which was located where trade caravans crossed the upper part of the Nile River.

a historian researching the immigration policies of the early 1900s would expect a source written today,rather than in 1910 to :

( a ) be more interested in objective data and statistics.

well that depends on how deep the hole is. you'd first go through te crust of the earth, then the upper mantle, then the lower mantle then the outer core, then the inner cor then you'd be stuck in the core to melt.