Question

dialysis is performed when a kidney a kidney is functioning. a kidney is failing. a kidney needs to be repaired.

Explanation:

Dialysis is a medical procedure used to filter waste and excess fluids from the blood when the kidneys are unable to perform this function adequately. If a kidney is functioning, dialysis is not needed. If a kidney needs repair, dialysis isn't the primary intervention for repair; it's for when the kidney fails to filter properly. So dialysis is performed when a kidney is failing.

Answer:

B. a kidney is failing. (assuming the options are labeled as A, B, C with A: a kidney is functioning, B: a kidney is failing, C: a kidney needs to be repaired)