What new developments in retail sales occurred in the late nineteenth century

I believe the answer is: Chain stores, mail order catalogs

Chain stores were made so a company could have broader reach to more consumers which are spread in different geographic locations. Mail order catalogs is a form of purchase that can be done through telephone. This is made in otder to target the consumers who do not want to waste time going to stores.

its many islands, high mountains, and remote peninsulas isolated population centers.

i do believe its (d) it allowed the government to offer pioneers sixty acres of western land if they lived on it and made improvements to it.

explanation: signed into law in may 1862, the homestead act opened up settlement in the western united states, allowing any american, including freed slaves, to put in a claim for up to 160 free acres of federal land. by the end of the civil war, 15,000 homestead claims had been established, and more followed in the postwar years