Why were the "Dark Ages" given this name? high levels of pollution caused an absence of light
guilt over abandoning traditional religions caused heightened anxiety
widespread illiteracy caused few historical records to be left behind
anger at the collapse of Rome caused political revolution

Correct answer is widespread illiteracy caused few historical records to be left behind .

Explanation:

First option is not correct as Europe didn't had problems with pollution, as they did with climate changes and diseases.

Second option is not correct as Christianity became a dominant part of everyday life of people.

Third option is correct as usually only people close to church were educated. Most of the people weren't able to leave any type of written source behind them.

There were no political revolutions at all at that time as the new feudal system was established.

they united the colonies in their fight against the british.