The function of cerebrospinal fluid surrounding CNS is to :

Options

A. Protect the brain from external jerks
B. Provide nOllrishment and `O_2` to the brain
C. Take away unwanted substance from the brain
D. All of these

Answer

**Step-by-Step Solution:**

1. **Understanding Cerebrospinal Fluid (CSF):**
- CSF is a clear, colorless fluid that surrounds the brain and spinal cord, forming a protective cushion.

2. **Function of CSF - Protection:**
- One of the primary functions of CSF is to protect the brain and spinal cord from external shocks and trauma. It acts as a buffer, absorbing impacts and preventing injury.

3. **Function of CSF - Nourishment:**
- CSF also plays a crucial role in supplying nutrients to the nervous system. It helps in delivering essential substances that are necessary for the proper functioning of the brain and spinal cord.

4. **Function of CSF - Waste Removal:**
- Another important function of CSF is to remove waste products that are generated from cerebral metabolism. This helps in maintaining a healthy environment for the neurons and other cells in the CNS.

5. **Conclusion:**
- Considering all the functions of CSF, it can be concluded that it serves multiple roles: protecting the CNS, nourishing it, and removing waste. Therefore, the correct answer to the question is that the function of cerebrospinal fluid surrounding the CNS is to protect, nourish, and remove unwanted substances.

**Final Answer:**
The function of cerebrospinal fluid surrounding the CNS is to protect the brain and spinal cord, nourish them, and remove unwanted substances (waste). Thus, the correct answer is "all of these."

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