Involuntary response process which require involvement of C.N.S without consicous effort is

Answer

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks for an involuntary response process that involves the Central Nervous System (CNS) without requiring conscious effort.

2. **Defining CNS**: The Central Nervous System (CNS) consists of the brain and spinal cord. It plays a crucial role in processing information and coordinating responses.

3. **Involuntary Responses**: Involuntary responses are actions that occur automatically without conscious thought. These responses are typically reflex actions.

4. **Reflex Action**: A reflex action is a rapid, automatic response to a stimulus. It does not involve conscious thought and is mediated by the spinal cord and brain.

5. **Example of Reflex Action**: A common example of a reflex action is the knee-jerk reflex. When a rubber hammer strikes the knee, it causes the leg to kick upward and then return to its original position. This is a classic demonstration of a reflex arc.

6. **Mechanism of Reflex Action**:
- **Stimulus**: The rubber hammer strikes the knee.
- **Sensory Neurons**: Sensory neurons detect the stimulus and send signals to the spinal cord.
- **Integration Center**: The spinal cord processes the information and sends signals through motor neurons.
- **Motor Neurons**: Motor neurons activate the muscles in the leg, causing the knee to jerk upward.
- **Response**: The leg moves upward and then returns to its original position.

7. **Conclusion**: Therefore, the involuntary response process that requires the involvement of the CNS without conscious effort is known as a **reflex action**.

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