Impedance represents tissue resistance and reactance; high impedance reduces current flow at a set voltage and influences dose and electrode contact quality.

• A. It represents tissue resistance and reactance; higher impedance reduces current flow at a fixed voltage and affects dose and contact quality.
• B. It is the speed of tissue healing during electrotherapy and should be minimized.
• C. It measures only tissue resistance and has no effect on dosage.
• D. It is the medical code used to bill therapy sessions.

Answer: (A)