What Is the Greatest Difference between Greek and Roman Architecture?

Good paper, Got a C+ on it. 3-4 when double spaced. Said there was some grammer mistakes
Greek Architecture
Greek architecture has been noted as some of the world's finest buildings known to man kind. Such as the Parthenon, and the temples they built to their Gods, have been studied over for many years. The way these structures were built is fascinating.
The Three Greek Orders of Architecture
Greek architecture is broken down into three orders. These orders were determined by the way that the top or capital of each column was sculpted. The first order was called the Doric Order. …