True about cross section study -

Ans. is 'd' i.e., All of the above Cross - sectional studiesCross sectional study is the simplest form of an observational study.It is also known as prevalence study.It is based on a single examination of a cross - section of population at one point of time.Results of this examination can be projected on the whole population.Cross-sectional study tells about the distribution of a disease rather than its etiology.Cross-sectional studies can be thought of as providing a snapshot of the frequency and characteristic of a disease in a population at a paicular point in time.Cross-sectional study is more useful for chronic disease.As population is studied at once, no follow-up is required.