<prompt> Case series report is a type of -Analytic studyExperimental studyObservational studyIntervention study  <response>: Ans. is c i.e., Observational study A Observational studiesi Descriptive studies : Case reports, case series.ii Analytic studies: Case-control case-reference, Cohort follow-up, Ecological correlational, Cross-sectional.B Experimentalintervention studiesi Randomized controlled trialsclinical trials. ii Field trials.iii Community trials.iv Animal studies. 