What is the purpose of a control group in an epidemiological study?

Correct Answer: C

Rationale: A control group (C) provides a baseline to compare outcomes, assessing exposure effects. A and B apply to trials, D is unrelated.

Correct Answer: B

Rationale: Etiology (B) is the study of disease causes (e.g., bacteria for TB). A, C, and D are consequences or responses.

Correct Answer: A

Rationale: Descriptive studies (A) generate hypotheses by observing patterns (e.g., cholera maps). B tests, C experiments, D is non-epidemiological.

Correct Answer: B

Rationale: Cohort studies (B) are observational, tracking natural exposure-outcome links. A and D are experimental, C is lab-based.

Correct Answer: B

Rationale: Analytical studies (B) test causal hypotheses (e.g., smoking and cancer). A is descriptive, C is generation, D is clinical.