A researcher studying a local school district realizes that its problems are also occurring in the majority of public-school districts within the U. S. This researcher is connecting to social phenomena."

Micro to Macro    

Explanation:

Micro-level social phenomena is the mechanism or happening taking place in the society at small level or low scale.E.g- in a group, in local area etc.

Macro-level social phenomena is the process that get processed at a large scale level in the society.E.g- social pattern etc.

According to the question,researcher is displaying micro to macro level social phenomena as he is researching the problem from local school level to public school level.

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.

its d i know cause i've been googling it