The most common and obvious fossils are the preserved skeletal remains of animals. Other fossils, which are also evidence of past organisms, include leaf impressions, tracks and trails, burrows, droppings, and root casts.
Lesson Summary. Non-experimental research does not mean nonscientific. Non-experimental research means there is a predictor variable or group of subjects that cannot be manipulated by the experimenter. Typically, this means that other routes must be used to draw conclusions, such as correlation, survey or case study.
Unobtrusive research (or unobtrusive measures) is a method of data collection used primarily in the social sciences.nobtrusive measures should not be perceived as an alternative to more reactive methods such as interviews, surveys and experiments, but rather as an additional tool in the tool chest of the social researcher.