The soldiers of the Terracotta Army all look exactly the same

Why did lincoln inform the confederacy that he would not e sending troops or weapons as food supplies were sent to fort sumter?

In exchange for land, a knight agrees to be a sort of sub-vassal to a vassal. this agreement was known as: investiture homage tyranny subinfeudation

Using mr smith and his id, identify two potential internal validity threats that might affect the a—b design. tell me how that threat might impact conclusions in the a—b design. note #1: you cannot use maturation (since i already did that one for note #2: there are some mr smith id threats that won’t have much impact in a single case design.