Which of the following happened first? the ice age the paleolithic era the mesolithic era the neolithic era

Hello!

The Ice Age happened before the Paleolithic, Mesolithic, and Neolithic eras. 
The Ice Age occurred roughly 2.6 million years ago, whereas the Paleolithic period only began about 12,000 years ago.

The Neolithic Era is the most recent of the options. The Mesolithic Era is the "middle era" which is in between the Paleolithic Era and the Neolithic Era. 

I hope this helps you! Have a great day!