This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Urinary tract, Subject name: Pathology
Renal calculi are commonly made up of 
Select and explain. 
A. Calcium oxalate, B. Magnesium ammonium phosphate, C. Uric acid, D. Cystine
A: Calcium oxalate
Answer: A: Calcium oxalate 
Explanation: There are four main types of kidney stones Calcium stones are the most common type of kidney stones. They are usually made of calcium and oxalate (a natural chemical found in most foods), but are sometimesmade of calcium and phosphate. Uric acid stones form when your urine is often too acidic. Refer robbins 9/e p951