Original sentence: The 14-by-6-foot mural depicting a white overseer and black slaves in 18th century Narragansett, RI, entitled "The Economic Activities of the Narragansett Planters", the painting's subject matter -- slavery -- disturbs some people, while others argue it's important to remember southern Rhode Island's plantation past
Edited sentence: The 14-by-6-foot mural depicting a white overseer and black slaves in 18th century Narragansett, RI, entitled "The Economic Activities of the Narragansett Planters", the painting's subject matter—slavery—disturbs some people, while others argue it's important to remember southern Rhode Island's plantation past