Your question is unsfecified
Trees 3-5 percent causing an increase in temperature and were dying from droughts that happened leaving dehydrated and dead vegetation and so, had no way of food to survive as many say "they did this to themselves" which I slightly agree with but that is some of what the Mayans lacked.
D- New Greek city-states we’re formed.
The answer is a "Hermit".
A hermit is a man who lives alone and apart from society, for the most part for religious reasons. In Christianity, the term was initially connected to a Christian who carries on with the eremitic life out of a religious conviction, to be specific the Desert Theology of the Old Testament i.e., the 40 years meandering in the desert that was intended to cause a change in heart.
Do you mean Alexander The Great?
Cavalry was important because soilders had to move from place to place instead of walking along the hot desert, which was very difficult.
hope this helps :)