How did airplanes change people lives/ society/ the environment? both pros and cons.

Airplanes brought several changes to our societies, lives and environment. Within the pros of this new mean of transport we can find the increase of the speed in which we travel and goods reach another shore. This affected positively the price of merchandises, which became easier to obtain around the world. What in the past was limited to be transported by land or across the sea, with the risk of never arriving, now it is very easy to obtain. Of course that they also opened a lot of new job opportunities for quite a few people. New careers were created and now a lot of people profit from this industry. Last but not least is the industry of tourism. Travelling has become much easier and practical since planes began to transport us.

On the other hand, the impact on the environment was not as good as in the others. Planes consume, and realease in the atmosphere, fosil fuels. This is limiting our natural resources at an incredible speed, apart from the fact that it contributes negatively to the matter of pollution.

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.