Which is a similarity between the Mayan, Aztec, and Inca civilizations?

The closeness between the Aztecs, Mayans and Incas is that all had control of monstrous realms that in the end stopped to exist. Other than that basic factor, the gatherings all had various lifestyles and one of a kind dialects, political plans, strict perspectives and approaches to accommodate their kin.

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.