Which of the following is not a function of kidney `:`

Options

A. Regulation of blood pressure
B. Removal of urea
C. Regulation of acidity of fluids
D. Secretion of antibiotics

Answer

To determine which of the following is not a function of the kidney, we will analyze each option provided:

1. **Regulation of Blood Pressure**: The kidneys play a crucial role in regulating blood pressure through the Juxtaglomerular Apparatus (JGA). When there is a decrease in the Glomerular Filtration Rate (GFR), the JGA secretes renin, which is part of the Renin-Angiotensin System (RAS) that helps to increase blood pressure. Therefore, this is indeed a function of the kidneys.

2. **Removal of Urea**: One of the primary functions of the kidneys is to filter and remove waste products from the blood, including urea, which is a nitrogenous waste product. This is a fundamental function of the kidneys. Hence, this option is also a function of the kidneys.

3. **Regulation of Acidity of Fluids**: The kidneys help maintain the body's acid-base balance by regulating the concentration of hydrogen ions (H+) and bicarbonate (HCO3-) in the blood. The Distal Convoluted Tubule (DCT) plays a significant role in this regulation by secreting ions to balance acidity. Thus, this is also a function of the kidneys.

4. **Secretion of Antibiotics**: The kidneys do not have a role in the secretion of antibiotics. They primarily function to filter blood, remove waste products, and regulate various bodily functions, but they do not secrete antibiotics. Therefore, this option is not a function of the kidneys.

Based on the analysis, the correct answer is **the secretion of antibiotics**, as it is not a function of the kidneys.

### Summary of the Solution:
- **Option 1**: Regulation of blood pressure - Function of kidneys.
- **Option 2**: Removal of urea - Function of kidneys.
- **Option 3**: Regulation of acidity of fluids - Function of kidneys.
- **Option 4**: Secretion of antibiotics - **Not a function of kidneys** (Correct answer).