During rest, the metabolic needs of the body are at their minimum. Which of the following Is indicative of this situation ?

Options

A. Rate of breathing
B. `O_(2)` intake `CO_(2)` output
C. Pulse rate
D. All of these

Explanation

To solve the question regarding the metabolic needs of the body during rest, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Metabolic Needs**: During periods of rest, the body's demand for energy and oxygen is significantly lower compared to when it is engaged in physical activity. This is because the body is not performing strenuous activities that require high energy expenditure.

2. **Identifying Key Indicators**: The metabolic needs can be indicated by several physiological parameters:
- **Rate of Breathing**: This will be at a minimum during rest since the body requires less oxygen.
- **Oxygen Intake**: The amount of oxygen the body takes in will also be minimal during rest.
- **Carbon Dioxide Output**: The amount of carbon dioxide expelled will decrease as the metabolic rate is lower.
- **Pulse Rate**: The heart rate will be lower during rest, reflecting the reduced demand for blood circulation to deliver oxygen and remove carbon dioxide.

3. **Comparing with Active States**: In contrast, during physical activities such as running, all these parameters (breathing rate, oxygen intake, CO2 output, and pulse rate) increase to meet the higher metabolic demands of the body.

4. **Conclusion**: Therefore, during rest, all the mentioned indicators (minimum rate of breathing, minimum oxygen intake, minimum CO2 output, and minimum pulse rate) are true. This leads us to conclude that the correct answer to the question is that all these indicators are indicative of the metabolic needs of the body during rest.

5. **Final Answer**: The answer to the question is **D) All of these**.