The correct option is Only 2.
Explanation
The kidney filters blood through nephrons, involving processes of filtration, reabsorption, and secretion.
- Statement 1: Incorrect – Clean (filtered) blood leaves the kidney through the renal vein, not the renal artery. The renal artery carries unfiltered blood into the kidney.
- Statement 2: Correct – After filtration in Bowman's capsule, the filtrate passes through renal tubules where essential substances such as glucose are reabsorbed into the blood and eventually returned via the renal vein.
Key Takeaway: Renal artery brings unfiltered blood to the kidney, while renal vein carries purified blood away after filtration and reabsorption processes.