In federalist no. 28, hamilton stated that the people would have an "instrument of redress," should they wish to challenge established power.
what was that instrument?

The correct answer is that the instrument that is being discuss on the Federalist paper No. 28 is the legal instrument which is the law.

Explanation:

The meaning of instrument of redress its that you can make a wrong right by compensation or any reward. This can be achieved by the legal system and the laws that are implaced for situations that need to be changed.

answer:

d. because dr. laguardia selected a widely used measure, his study generalizes to has strong external validity. external validity has limited external validity. other applications of this measure.

the widely used measure that he applied to his experiment was the benton facial recognition test. it employed on to football players and as result, only players who suffered brain concussions did not pas this test. and although it has an external validity, it is limited because it isn't general to apply to other population.