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.
Animal research redirects here. For other uses, see Animal studies (disambiguation). Animal testing, also known as animal experimentation, animal research and in vivo testing, is the use of non-human animals in experiments that seek to control the variables that affect the behavior or biological system under study.