Which u. s.-originated sport is popular in canada?

Which of there factors contributed most to us westward expansion in the second half of the nineteenth century?

The rocky mountain system stretching from canada to new mexico is a string of mountains running along the wester united states. what factors would mostly cause this arrangement of mountains? intense pressure undemeath a tectonie plate that could not breakthrough the rock subduction of a tectonic plate, which pushed up a neighboring plate into mountains two plates located at a diverging boundary with a third plate rising between them two plates that melted into molten rock, which later cooled into the shape of mountains

Can someone list any possible solutions to air pollution ?