How did the Renaissance lead to a rebirth of knowledge and learning?

The Renaissance: rebirth of learning. By the 1500's the humanistic ideals of new thinking spread across the Alps and into northern European countries. Many students began to travel to Italy to learn in the center of the Renaissance and study at Italian universities. ... This was known as christian humanism.

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.