For the first question I can give you a few important achievements but to put it in your own words you should describe them yourself.
Important Mayan achievements: architecture, astronomy, and math. Myans were great builders and built many roads, cities, and temples with intricate designs. This is just some information about the maya.
Fun fact: I am actually taking a test in mesoamerican civilizations tomorrow. I got this straight from the slides the teacher made.
Hope I could help, Good Luck!