Distinguish between continuous and pulsed currents regarding tissue response and safety.

• A. Continuous currents are safer than pulsed currents.
• B. Pulsed currents cause less selective activation.
• C. Continuous currents are less likely to cause polarization.
• D. Continuous currents can cause polarization and skin irritation; pulsed currents deliver discrete bursts, reducing side effects and enabling selective activation.

Answer: (D)