How do scientists determine whether or not to set the clock ahead or back?

In an industry in which there are several providers of a type of good, why can one business not charge much higher prices for their goods?

What two different approaches did the knights of labor and the american federation of labor take in building a union organization? a) the knights of labor accepted only unskilled workers; the american federation of labor accepted only skilled workers. b) the knights of labor accepted skilled and unskilled workers; the american federation of labor accepted only skilled workers.c) the knights of labor refused to accept african american or chinese workers; the american federation of labor accepted all workers.d) the knights of labor accepted workers from a single industry; the american federation of labor accepted workers from several industries.

How does he election of president andrew jackson illustrate the nation’s westward growth?