Select the correct statement .

Options

A. Humans possess 1 million nephrons
B. Glomerulus is not the part of nephron
C. Kidneys collectively filter one fifth of the total blood of body in a minute .
D. Collecting ducts are found in medulla only

Answer

To solve the question, we need to analyze each of the four statements provided and determine which one is correct.

### Step-by-Step Solution:

1. **Evaluate the First Statement: "Humans possess 1 million nephrons."**
- Nephrons are the structural and functional units of the kidneys.
- Each human kidney contains approximately 1 million nephrons, which means that in total (both kidneys), a human has about 2 to 2.5 million nephrons.
- Therefore, this statement is **incorrect**.

2. **Evaluate the Second Statement: "Glomerulus is not the part of nephron."**
- The nephron is divided into three main parts: the renal corpuscle, renal tubule, and associated capillary network.
- The renal corpuscle includes the glomerulus and Bowman's capsule.
- Since the glomerulus is indeed a part of the nephron, this statement is also **incorrect**.

3. **Evaluate the Third Statement: "Kidneys collectively filter one-fifth of the total blood of the body in a minute."**
- The kidneys filter a significant amount of blood, but they filter approximately 1/4 (or one-fourth) of the total cardiac output, which is roughly 1.2 to 1.5 liters per minute.
- This statement is misleading as it suggests a different fraction than what is accurate, hence it is **incorrect**.

4. **Evaluate the Fourth Statement: "Collecting ducts are found in medulla only."**
- The collecting ducts are indeed located in the medulla of the kidney.
- The distal convoluted tubule (DCT) opens into the collecting duct, which then converges and opens into the renal pelvis through the medullary pyramids.
- Therefore, this statement is **correct**.

### Conclusion:
The correct statement is: **"Collecting ducts are found in medulla only."**

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