In frog kidney, the urea is eliminated by

Options

A. glomerular filtration
B. tubular secretion
C. both (a) and (b)
D. tubular absorption

Answer

To solve the question regarding how urea is eliminated in the frog kidney, we can break down the process step by step:

### Step-by-Step Solution:

1. **Understanding Urea Excretion**:
- Urea is a waste product formed from the breakdown of proteins. In frogs, like in many other organisms, it needs to be excreted from the body.

2. **Kidney Functions**:
- The kidneys play a crucial role in filtering blood and removing waste products. In frogs, the kidneys are responsible for the elimination of urea.

3. **Processes of Elimination**:
- There are two primary processes involved in the elimination of urea in the kidneys:
- **Glomerular Filtration**: This is the first step where blood is filtered in the glomerulus of the nephron. During this process, urea, along with other small molecules and water, is filtered out of the blood into the renal tubule.
- **Tubular Secretion**: This process involves the active transport of substances from the blood into the renal tubule. While this process is primarily associated with the secretion of certain ions and the reabsorption of water, it also plays a role in the elimination of urea.

4. **Conclusion**:
- Both glomerular filtration and tubular secretion contribute to the elimination of urea in the frog kidney. Therefore, the correct answer to the question is that urea is eliminated through both glomerular filtration and tubular secretion.

### Final Answer:
Urea is eliminated by both glomerular filtration and tubular secretion in the frog kidney.