What are some of the unique elements of roman art and architecture that distinguish it from greek and other art of the same time period?

The Roman art's the unique elements are Roman ancestor portraits, former slaves, and Roman House. Funerary relief with portraits of the Gessii is one of example. Roman builders used of concrete. Most innovative use of concrete constructionwas in the Sanctuary of Fortuna Primigenia with its terraces, ramps, shops, and porticos spread out over several levels