Input: Article: One result of debates over the meaning and validity of the concept of race is that the current literature across different disciplines regarding human variation lacks consensus, though within some fields, such as some branches of anthropology, there is strong consensus. Some studies use the word race in its early essentialist taxonomic sense. Many others still use the term race, but use it to mean a population, clade, or haplogroup. Others eschew the concept of race altogether, and use the concept of population as a less problematic unit of analysis.

Now answer this question: What is a less problematic unit of analysis?

Output: concept of population

Input: Article: Some definitions of southern Europe, also known as Mediterranean Europe, include the countries of the Iberian peninsula (Spain and Portugal), the Italian peninsula, southern France and Greece. Other definitions sometimes include the Balkan countries of southeast Europe, which are geographically in the southern part of Europe, but which have different historical, political, economic, and cultural backgrounds.

Now answer this question: What nations are sometimes included in the scope of southern Europe?

Output: Balkan countries

Input: Article: The formal study of adolescent psychology began with the publication of G. Stanley Hall's "Adolescence in 1904." Hall, who was the first president of the American Psychological Association, viewed adolescence primarily as a time of internal turmoil and upheaval (sturm und drang). This understanding of youth was based on two then new ways of understanding human behavior: Darwin's evolutionary theory and Freud's psychodynamic theory. He believed that adolescence was a representation of our human ancestors' phylogenetic shift from being primitive to being civilized. Hall's assertions stood relatively uncontested until the 1950s when psychologists such as Erik Erikson and Anna Freud started to formulate their theories about adolescence. Freud believed that the psychological disturbances associated with youth were biologically based and culturally universal while Erikson focused on the dichotomy between identity formation and role fulfillment. Even with their different theories, these three psychologists agreed that adolescence was inherently a time of disturbance and psychological confusion. The less turbulent aspects of adolescence, such as peer relations and cultural influence, were left largely ignored until the 1980s. From the '50s until the '80s, the focus of the field was mainly on describing patterns of behavior as opposed to explaining them.

Now answer this question: Which theorist is known for his beliefs on evolution?

Output:
Darwin