The part of the kidney where the selective reabsorption takes place is

Analyze the question: It asks where selective reabsorption occurs in the kidney, meaning the place where useful substances (glucose, amino acids, water, salts) are taken back into the blood after filtration.

Explain the concept: Urine formation in the nephron has three main stages:

1. Ultrafiltration happens at the glomerulus and Bowman's capsule. Blood is filtered under high pressure, and water, glucose, salts, urea and amino acids pass into the capsule.
2. Selective reabsorption happens along the renal tubule. Most of it takes place in the proximal convoluted tubule, where all the glucose and amino acids and much of the water and salts are reabsorbed. The loop of Henle and the distal tubule also reabsorb water and salts.
3. Secretion and excretion move the remaining fluid (urine) through the collecting duct to the ureter, bladder and then the urethra.

Step-by-step evaluation of the options:

• A. Glomerulus: This is the site of filtration, not reabsorption. ✗
• B. Bowman's capsule: This collects the filtrate. ✗
• C. Henle's loop: This is part of the renal tubule, where water and salts (especially sodium and chloride) are reabsorbed, so it is the only option that takes part in selective reabsorption. ✓
• D. Urethra: This only carries urine out of the body. ✗

A note on the answer: The best answer in textbooks would be the proximal convoluted tubule, but it isn't listed. Among the given options, only the loop of Henle is part of the tubule where reabsorption occurs.

Answer: C. Henle's loop

Exam tip: Remember the order G-B-P-H-D-C: Glomerulus → Bowman's capsule → Proximal tubule → Henle's loop → Distal tubule → Collecting duct. Filtration happens at the first two. Reabsorption happens in the tubule parts that follow. If the question lists only one tubule part, choose it.