Final answer:
J.M.W. Turner's work in 'Gateways to Art 3rd Edition' showed social conscience through his subject matter and artistic choices, including politically inspired paintings like 'The Slave Ship.'
Step-by-step explanation:
J.M.W. Turner's work in our textbook, Gateways to Art 3rd Edition, demonstrated social conscience through his subject matter and artistic choices. Turner incorporated elements of landscape, weather, and sea travel into his work, often focusing on awe-inspiring or horror-inducing subjects. One example of this is his painting 'The Slave Ship,' which was politically inspired and depicted a shipwreck. You can find a good analysis of this painting at this link.