In the 1970s, a 13-year-old girl was found locked up in a room, strapped to a potty chair. since she had grown up in a world without human speech, researchers studied "genie's" ability to acquire words, grammar, and pronunciation. this type of research is called a case study representative sample single-blind study naturalistic observation

I believe the answer is: Case study

Case study refers to a form of research that includes in-depth and detailed examination toward a certain subject study as its method of collecting data. Case study is the type of research that's the most popular by researchers in formal work background/ settings.

answer; conventional stage;

answer; traffic,pedestrians,parked vehicles and intersections;