Answer:
A. 74
Explanation:
The given mortality rate is understood to be <em>deaths per thousand per year</em>. So, among 10 thousand people, one might expect 10×7.4 = 74 deaths per year.
Something must have been moving along and either plowed the stuff to one side or carried it and deposited it along the side. What else but a glacier?
PS. I'd guess this is more the province of geologists, not geographers
Night is cool but the real answer is daylight
