Case control study method has following three distinct features. Select inappropriate one

Case control Study - Case control studies, often called as"retrospective 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.