Which statement correctly defines incidence and prevalence?

Which statement correctly defines incidence and prevalence?

• A. Incidence is total existing cases; prevalence is new cases.
• B. Incidence measures mortality; prevalence measures recovery.
• C. Incidence and prevalence are the same.
• D. Incidence is the number of new cases in a population over a period, while prevalence is the total number of existing cases at a point or period.

Answer: (D)