Renal tubules are crucial for what process?

• A. Filtration of blood
• B. Production of urine
• C. Reabsorption of substances
• D. Secretion of waste

Answer: (C)

Renal tubules play a vital role in the reabsorption of substances, which is essential for maintaining the body's fluid and electrolyte balance. After the initial filtration of blood in the glomeruli, the filtrate enters the renal tubules, where important substances such as glucose, amino acids, and ions are reabsorbed into the bloodstream. This process ensures that valuable nutrients and necessary water are retained, while waste products remain in the tubular fluid to be excreted as urine.

While filtration of blood, production of urine, and secretion of waste are associated with kidney function, reabsorption is the specific process carried out by the renal tubules that directly adjusts the composition of the filtrate. By selectively reclaiming substances, renal tubules fine-tune the body's internal environment, preventing excessive loss of essential compounds.