Self sufficiency of Medival Europe helped to promote Medieval Europe's "Dark Age" because:

A
it slowed trade, travel and the sharing of ideas

B
it encouraged people to challenge religious ideas

C
it led to the mass production of books

D
it kept the serfs bound to their lord's land

The myth of the Middle Ages as a “dark age” does not lie in the fact ... With long-distance trade at a low ebb, European farmers had to be far more self-sufficient, and ... These false ideas are still current partly because historians have only ... Reprints; Advertise: Site / Podcasts · Commenting · Podcast FAQs ...

Explanation:

i think the answer is c, rivers.

explanation:

sometimes, borders fall along natural boundaries like rivers or mountain ranges. for example, the boundary between france and spain follows the crest of the pyrenees mountains. for part of its length, the boundary between the united states and mexico follows a river called the rio grande. the borders of four countries divide africa’s lake chad: niger, chad, cameroon, and nigeria.

lincoln declared that slavery should not be allowed to spread into the new states, and of course this angered the south at the time.