Which of the following option is correct about the excretory system in human ?

Options

A. GFR : 125 ml/ day
B. Urine output : 180 litre / day
C. Urea excretion : 25 - 30 mg/day
D. `CO_2` removal: 0.9 -1 kg/day/ human

Answer

To solve the question regarding the excretory system in humans, we will analyze each option provided in the question and determine which one is correct.

### Step-by-Step Solution:

1. **Understanding the Glomerular Filtration Rate (GFR)**:
- The GFR is the rate at which blood is filtered in the kidneys. It is typically measured in milliliters per minute.
- The average GFR is approximately 125 ml/min, which translates to about 180 liters of filtrate produced per day. However, the question states "125 ml per day," which is incorrect.

**Hint**: Remember that GFR is measured in ml/min, not ml/day.

2. **Evaluating Urine Output**:
- The filtrate produced by the kidneys is around 180 liters per day, but due to reabsorption processes, the actual urine output is about 1.5 liters per day.
- The statement regarding urine output being 180 liters per day refers to the filtrate, not the urine that is excreted.

**Hint**: Distinguish between the volume of filtrate produced and the volume of urine excreted.

3. **Analyzing Urea Excretion**:
- Urea is a waste product formed from protein metabolism. The typical excretion of urea in humans is about 25 to 30 grams per day, not micrograms.
- Therefore, the statement claiming urea excretion is 25 to 30 micrograms per day is incorrect.

**Hint**: Recall the typical range of urea excretion in grams, not micrograms.

4. **Considering CO2 Removal**:
- Carbon dioxide (CO2) is primarily removed from the body through respiration via the lungs. The amount of CO2 excreted is about 200 ml per minute, which sums up to much less than 0.9 to 1 kg per day.
- Thus, the statement regarding CO2 removal being 0.9 to 1 kg per day is also incorrect.

**Hint**: Remember that CO2 is exhaled and its quantity is measured in ml/min, not kg/day.

5. **Conclusion**:
- After evaluating all the options:
- Option 1 (GFR is 125 ml per day) is incorrect.
- Option 2 (Urine output is 180 liters per day) is misleading, as it refers to filtrate, not urine output.
- Option 3 (Urea excretion is 25 to 30 micrograms per day) is incorrect.
- Option 4 (CO2 removal is 0.9 to 1 kg per day) is incorrect.
- The correct interpretation is that while the kidneys filter around 180 liters of filtrate daily, the actual urine output is about 1.5 liters.

### Final Answer:
The correct statement regarding the excretory system in humans is that the kidneys filter approximately 180 liters of filtrate per day, but only about 1.5 liters is excreted as urine.

**Correct Option**: None of the options provided are entirely correct based on the analysis. However, if the question is interpreted as asking for the correct understanding of urine output, option 2 can be considered correct in the context of filtrate production.