Henry clay american system: which points did we actually pass?

One common educational practice is to chart students' progress over time so that students can see their own improvement. these progress charts often lead to higher student achievement in the absence of other observable forms of reinforcement. the effectiveness of such charts in changing behavior illustrates the role of reinforcement as:

The law of supply states-when price increases, the quantity will when prices decreases the quantity supplied will we look at supply from the point of view .’

Which environmental change allowed people to travel by land between asia and north america a.human apaption to arctic environments b.the introduction to horses to north america c.the formation of ice sheets on land d.a rise in ocean temperatures