Cananswer this real quick PLEASE I BEG

What greek scientist created a screw to move water for irrigation?

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.

Whose political philosophy is mostly clearly reflected in the declaration of independence