Which is true abut excretion ?

Options

A. 90% water and `Na^(+)` of glomerular filtrate are absorbed
B. Glucose is reabsorbed in distal convoluted tubule
C. Glucose is reabsorbed in proximal convoluted tubule
D. 99% of water and glucose in the glomerular filtrate are reabsorbed.

Answer

To determine which statement about excretion is true, we will analyze each statement provided in the question step by step.

### Step-by-Step Solution:

1. **Statement Analysis**:
- **Statement 1**: "90% water and sodium ions of glomerular filtrate are absorbed."
- This statement is incorrect. The correct percentage is approximately 99% of water that is reabsorbed from the glomerular filtrate, not 90%. Additionally, while sodium ions are reabsorbed, the focus here is on the percentage of water.

2. **Statement 2**: "Glucose is reabsorbed in distal convoluted tubule."
- This statement is also incorrect. Glucose is not primarily reabsorbed in the distal convoluted tubule (DCT). Instead, it is reabsorbed earlier in the nephron.

3. **Statement 3**: "Glucose is reabsorbed in proximal convoluted tubule."
- This statement is incorrect. Glucose is indeed reabsorbed in the proximal convoluted tubule (PCT), but the statement is misleading as it implies that this is the only site of reabsorption. However, it is important to note that glucose is primarily absorbed in the PCT.

4. **Statement 4**: "99% of water and glucose in the glomerular filtrate are absorbed."
- This statement is correct. The kidneys filter about 180 liters of fluid daily, and out of this, approximately 1 to 1.5 liters are excreted as urine. This means that around 178 to 179 liters of fluid, which includes both water and glucose, are reabsorbed by the body.

### Conclusion:
Based on the analysis, the correct statement about excretion is:
- **Correct Answer**: Statement 4 - "99% of water and glucose in the glomerular filtrate are absorbed."