What is the purpose of a negative control and a positive control in a rodent biomedical experiment?

• A. Negative control receives no active treatment and should show no effect; positive control receives a known active treatment and should demonstrate a response; both validate assay sensitivity.
• B. It helps calibrate instruments used in the lab.
• C. It determines the sample size needed for statistical power.
• D. It has no impact on study outcomes.

Answer: (A)