In humans, water is

Options

A. found in the glomerular filtrate
B. reabsorbed from the Collecting duct
C. in the urine
D. All of these

Answer

To answer the question "In humans, water is...", we will analyze the different contexts in which water is found in the human body, particularly focusing on the kidneys and urine production.

### Step-by-Step Solution:

1. **Understanding Glomerular Filtrate**:
- Water is present in the glomerular filtrate, which is the fluid that is filtered from the blood in the kidneys. This filtrate is formed in the glomerulus, a network of capillaries in the nephron.
- **Hint**: Remember that glomerular filtrate is the first step in urine formation.

2. **Role of the Nephron**:
- The nephron is the functional unit of the kidney and consists of two main parts: the glomerulus and the renal tubule. The renal tubule is where further processing of the filtrate occurs.
- **Hint**: Think of the nephron as a factory where blood is processed to form urine.

3. **Water Reabsorption**:
- As the filtrate moves through the renal tubule, especially in the collecting duct, a significant amount of water is reabsorbed back into the bloodstream. This process helps maintain the body's water balance.
- **Hint**: Consider how the body conserves water, especially in conditions of dehydration.

4. **Presence in Urine**:
- Ultimately, the remaining water that is not reabsorbed becomes part of the urine, which is excreted from the body. Urine contains water along with waste products.
- **Hint**: Think about the composition of urine and its role in excretion.

5. **Conclusion**:
- Since water is found in the glomerular filtrate, is reabsorbed from the collecting duct, and is also present in urine, all the options provided in the question are correct.
- Therefore, the correct answer is that water is found in all of these contexts in humans.

### Final Answer:
Water is found in the glomerular filtrate, is reabsorbed from the collecting duct, and is present in urine. Thus, the correct answer is option 4: all of these.