It was primarily "<span>d. the vulnerability to invaders from the north", since the Mongol territory was rapidly expanding--making the Mongol warriors all the more powerful. </span>
<span>Assuming that this is referring to the same list of options that was posted before with this question, <span>the correct response would be the one having to do with "customer support centers for American companies" being based overseas, since this shows the extent of corporate and national interconnectedness. </span></span>
The main reason why such a large portion of the population during this time in the United States shifted from rural to urban areas was because industrialization had created many more employment opportunities in the city factories.
I drank coffee in the afternoon and now i’m bored so i am here listening to some blonde by frank ocean ♂️