Biology: Zoology: UPSC Previous Year Questions (Science and Technology)

Explanation

Option (c) is correct: The major chemical compound that constitutes kidney stones is Calcium Oxalate. These stones are common and can cause severe pain during urination. Calcium oxalate is formed when calcium in the urine binds with oxalate, a compound found in certain foods (e.g., spinach, nuts) or produced as a by-product of metabolism. High concentrations of calcium and oxalate in urine, combined with low fluid intake, promote the crystallization of calcium oxalate. Options (a), (b), and (d) are incorrect: Urea is not a major component of kidney stones because it is a waste product of protein metabolism that is typically excreted in the urine. Other types of kidney stones can contain calcium carbonate, calcium phosphate, uric acid, or struvite, but calcium oxalate stones are the most common. Factors such as dehydration, high oxalate intake, and certain medical conditions can increase the risk of kidney stone formation.