A "Shared environment influence", they aren't currently in a shared environment. B,fraternal would be like brotherly influence, which is clearly wrong if we're focusing on their time apart. D, what would the teachers have to do with their genetic influence? they aren't related to the identical twins (not that we know of). so that leaves C: this would be the most likely considering their environment (their surroundings?) are different {nonshared environmental influence}. im not certain though.
Powerful empires were built, Written and spoken languages were made and perfected, and new technology was created
Um..that cant happen because you need to give us details
First, it all began with the conflict between the settlers and the indian tribes. There were a lot of of massacres that being done to the native tribes, resulting in thousands of death ( such as Sand Creek Massacre or little big horn battle).
Since the settlers generally won the battle, they created Dawes Severalty Act, which dismantled the tribes and make them assimilate among the settlers.
This provide the opportunity for the railroad company to come in and transform the trans- Mississippi west