Simplify the following text for a Grade 12 native English-speaking person.
Original: The Mesolithic ( Greek : mesos `` middle '' , lithos stone ) or `` Middle Stone Age '' was a period in the development of human technology in between the Paleolithic or Old Stone Age and the Neolithic or New Stone Age , in which farming appeared .
Simplified: The Mesolithic was a period in the development of human technology between the Paleolithic and Neolithic periods of the Stone Age .