Answer:
"When Julius Caesar crossed the Rubicon, he started a five-year Roman civil war. ... Therefore, by crossing the Rubicon into Gaul and starting the war, Caesar threw the dice, not only sealing his own political future but effectively ending the Roman Republic and beginning the Roman Empire."
or
"Faced with the intransigence of the Senate, Caesar and the 13th Legion cross the Rubicon, the official border between Gaul and Italy, a decision that will lead to civil war. As Caesar advances on Rome, Pompey and his allies retreat south, ultimately abandoning Italy for Greece. Caesar defeats Pompey's forces in Spain."
Explanation:
I hope this helps, I am sorry if it doesn't
It's most likely that the Mayans abandoned their cities but no one knows why
A. Farmers struggled to find markets for their goods as prices began to drop
