Why Are There So Many Different "clicks' In U.S. Schools?

There are possibly different clicks that exist in the United States school, due to reasons like culture, family backgrounds, individual lifestyle and one of the main reasons could be different individuals coming from across the globe.

Generally there are many students from various countries like India, Australia, etc. and these students for obvious reasons differ in backgrounds. When these students come together under an institute they are bound to form a group among themselves, rather then bonding with the rest. Another main reason would be that these groups are the variation in lifestyle among the school kids of America themselves.