What is the difference between problem/solution and cause/effect?

Hillenbrand writes, "as louie blazed through college, far away, history was turning" (p. 43). why does the author interrupt louie's narrative with information about japan and germany?

Something there is that doesn't love a wall, that sends the frozen-ground-swell under it, and spills the upper boulders in the sun; and makes gaps even two can pass abreast. the work of hunters is another thing: i have come after them and made repair where they have left not one stone on a stone, but they would have the rabbit out of hiding, to the yelping dogs. the gaps i mean, no one has seen them made or heard them made, but at spring mending-time we find them there. whom does the speaker blame for the gaps in the wall? himself his neighbor nature and hunters rabbits and dogs

Which does not contain a run-on sentence? a. using the big dipper, you can find the north star, just follow an imaginary line through the dipper's two end stars. b. using the big dipper, you can find the north star just follow an imaginary line through the dipper's two end stars. c. using the big dipper, you can find the north star by following an imaginary line through the dipper's two end stars. d. using the big dipper; find the north star just follow an imaginary line through the dipper's two end stars.