Answer:
The kidney is tested to see whether it is suitable for donation by checking for diseases and conditions that could make it unsuitable for transplantation.
The rejection of the new kidney is a problem because it is not able to remove waste from the blood properly. The nephrons inside the kidney are not able to filter the blood properly and the waste accumulates in the body. The body then has to find a way to remove the waste and this can be done through dialysis or a transplant.
Step-by-step explanation: