What is a risk factor?

Correct Answer: C

Rationale: A risk factor (C) increases disease likelihood (e.g., smoking for lung cancer). A is causation, B reduces risk, D is intervention.

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.

Correct Answer: D

Rationale: All methods (D) control confounding: randomization (A) balances variables, blinding (B) reduces bias, matching (C) pairs on confounders (e.g., age). Combined, they’re effective.