"<span>because the trend of Chinese immigrants to large urban cities harmed the industrialization of the US economy" is the best option but there were wavering levels of truth to this. </span>
This is true. The British army was much larger and much more developed, but the colonial army managed to win by winning the support of the people and of foreigners. They were helped by British enemies such as France who was willing to give not only weapons and money, but also its navy and its generals with their war expertise.
Variation in the relative frequency of different genotypes in a small population, owing to the chance disappearance of particular genes as individuals die or do not reproduce.