Because of differential opportunities presented to youth, disadvantaged young people are likely to join one of three types of gangs; the gangs that develop because youth are double failures, both unable to gain legitimate means and unwilling to do so through illegal means, are called gangs.

The answer is - Retreatist

Explanation:

There are three types of gangs which young people are likely to join and they are; Criminal, Conflict, Retreatist gang. The retreatist gang are gangs that develop because the youth are unable to be successful through legal means and are also unwilling to do so through illegal means. They therefore use drugs and alcohol as a means of escape from reality and are constantly looking for ways to get high.

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.