Concept:The kidney is the main organ that controls the amount of water in the blood and removes the greatest volume as urine.
Explanation:The blood is constantly filtered by the kidneys.
Excess water, along with dissolved waste products, is separated from the blood to form urine.
This process helps maintain the body's fluid balance.
Water is also lost through the skin as sweat, through the lungs as breath vapour, and through the intestine in faeces.
However, the quantity of water removed by the kidneys is far larger than the total lost through these other organs.
Answer:C. Kidney