What role did the bantu have in the development of swahili culture?
a. they dominated the culture along the coast.
b. they spread the culture throughout western africa.
c. they brought elements of islam into the culture.
d. they influenced changes in language and culture.

porter is writing economic history because he is focusing on the cost of developing vaccines.

in the 1800s, locomotives powered by steam made transportation faster and cheaper. the resulting rapid growth of railroads led to the connection of the atlantic and pacific railroad in oklahoma city in 1897.

in the last years of the century, the improvement of steam-based engines the expansion and growth of railroads. this growth increased when the companies started to build and expand, such as the atlantic and pacific railroad, which connected new mexico with california, and missouri with oklahoma. many of these new networks were built in oklahoma, and these changes transportation henceforward.