Below is an instruction from Human. Write a response.
    ### Instruction:
    What is (are) Chronic Kidney Disease ?
    ### Response:
    You have two kidneys, each about the size of your fist. Their main job is to filter wastes and excess water out of your blood to make urine. They also keep the body's chemical balance, help control blood pressure, and make hormones.    Chronic kidney disease (CKD) means that your kidneys are damaged and can't filter blood as they should.
    