contestada

The most significant obstacle in building the Transcontinental Railroad was
a.)crossing the Appalachian Mountains.
b.)laying track across the Great Plains.
c.)removing hostile Native Americans from the region.
d.)crossing the Sierra Nevada Range and the Rocky Mountains.

Respuesta :

I know it's from the rugged region, so I would go with D, because they had trouble through the desert, and the mountains.

i think the answer is d