What is a citizen? who is a citizen of the united states? how do you become a naturalized citizen of the united states? (what are the untied states naturalization requirements? ) what are the rights of a citizen of the united states? what are the responsibilities of a citizen of the united states? how do you become an informed citizen? what problem-solving techniques will you make good decisions? what can kids do to get involved in being good citizens? how can kids get involved in their communities?

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.

can you explain it better