American settlers started moving west because they wanted a better life, a big factor of settlers moving west was also for land since it was very cheap, also gold and mining opportunities.
Christina Aguilera has sold over 50 million albums worldwide<span>.</span>
In this passage, the type of warfare being described by the author is "chemical warfare".
He helped <span>to develop the scientific method which in summary is.</span>
The first American railroads carried <span>passengers and freight.</span>
