It was Lev V<span>ygotsky, a Soviet psychologist, who theorized about the aided and the preceded concepts regarding the development of language. His theory was mainly focused on human bio-social and cultural development and for him interaction is a necessary tool in one's development.</span>
this should help you I hope
WW2 I believe/think. That would be my answer.
I believe the answer is :Random sampling
Random sampling refers to select a group of subjects that could be used as sample for a research from a large population. The selection is beind done without any criteria in hope that the sample at least represent the general composition of the population.