The Italian explorer Marco Polo brought back glowing reviews of Mongol rule in China. Why should we believe those accounts?

As neither Mongol nor Chinese, Marco Polo could observe and report on Kublia's empire without bias.

Marco Polo was able to unite the Chinese and Mongol people with his kind words about Kublai Khan.

Marco Polo was paid by the Khan to make him look good to rulers in Western Europe.

Marco Polo had described Genghis Khan as a torturer and was glad to see that the grandson was different.

As neither Mongol nor Chinese, Marco Polo could observe and report on Kublia's empire without bias.  

Explanation:

lincoln presided over the union victory in the american civil war, which dominated his presidency. a former whig, lincoln ran on a political platform opposed to the expansion of slavery in the territories. his election served as the immediate impetus for the outbreak of the american civil war.

biological/genetic factors means they were born or predisposed to have something. nothing can really change it, and you can't really do much to "fix" it. it isn't something learned

these are the biological factors:

adrian is relatively tall and he is on the basketball team

(adrian can't ever stop being tall or force himself to be tall. likely one or both of his parents are tall as well and they passed on the tall gene. he probably does basketball because he is tall)

the rest are environmental/cultural factors. these are things that are taught to us. for example, cynthia wasn't born saving pocket money, her family most likely taught her this (environmental factor)

hope this !