Answer:
Another reason why the Middle Ages are often called the Dark Ages is because, compared with other eras, historians don't know as much about this time. In some ways, this period of time has been lost to history. Many important records from this time have not survived.
Explanation:
you can say according to the article they are called Middle ages because of the black death.
Earth's atmosphere is 78% nitrogen, 21% oxygen, the rest 1 percent with very small percentages of other elements like Co2.
Classical art is the paintings, sculptures and architectures of Ancient Greece and Rome.
The correct answer is c. <span>After overthrowing the Song Dynasty, he moved the imperial capital from Beijing to Mongolia
Kublai Khan was Mongolian himself, so a. would not make sense.
Kublai Khan move the capital to Shangdu initially, but later moved it to what is today Beijing.</span>
