The main function of the kidneys is to:
a. remove toxins from urine.
b. remove everyday wastes and water from the body
c. remove carbon dioxide from the blood and excrete it in urine.
d. store extra glycogen for use in emergencies by the body
e. retrieve vital nutrients from urine and send them back to the liver for processing.

A62-year-old man is being treated for an acute myocardial infarction. he originally came to the ed with substernal chest pain and diaphoresis. given his risk factors of hypertension, diabetes, tobacco use, and family history, he is considered high risk. an ecg in the ed reveals a left-bundle branch pattern, and cardiac enzymes are elevated slightly. after a focused evaluation in the ed, the patient receives iv thrombolytics. although his bundle branch pattern never resolves, the patient is chest pain-free and haemodynamically stable after thrombolysis. two days later, however, the patient reports episodes of recurrent chest discomfort and shortness of breath overnight. in evaluating for potential myocardial reinfarction, which of the following is the most appropriate diagnostic test? - creatinine kinase- dynamic ecg changes- lactate dehydrogenase- myoglobin levels- troponin i level