<prompt> Case control study method has following three distinct features. Select inappropriate oneBoth exposure and outcome have occurred before the sta of the studyUnit of study is group rather than individualThe study proceeds backward from effect to causeIt uses a control or comparison group to suppo or refute an interference  <response>: Case control Study - Case control studies, often called asretrospective studies .It has 3 distinctive features both exposure and outcome disease have occurred before the sta of the study. the study proceeds backwards from effect to cause. it uses a control or comparison group to suppo or refute an inference. - In case control studies,the unit is individual rather than the group. EXTRA EDGE: UNIT OF STUDY: Coho study, Case control study, Cross sectional study - Individual Ecological study, Descriptive study - Population. 