From the following relationship between respiration volumes and capacities, mark the correct option.
(i) Inspiratory Capacity (IC) `=` Tidal Volume + Residual Volume
(ii) Vital Capacity (VC) = Tidal Volume (TV) + Inspiratory Reserve Volume (IRV) + Expiratory Reserve Volume (ERV)
(iii) Residual Volume (RV) = Vital Capacity (VC) - Inspiratory Reserve Volume (IRV)
(iv) Tidal Volume (TV) = Inspiratory Capacity (IC) - Inspiratory Reserve Volume (IRV)

Options

A. I incorrect ii incorrect iii incorrect iv correct
B. I incorrect ii correct iii incorrect iv correct
C. I correct ii incorrect iii correct iv correct
D. I correct ii incorrect iii correct iv incorrect

Answer

To solve the question regarding the relationships between respiratory volumes and capacities, we will analyze each statement one by one based on the definitions of the terms involved.

### Step-by-Step Solution:

1. **Understanding the Terms**:
- **Tidal Volume (TV)**: The amount of air inhaled or exhaled during normal breathing.
- **Inspiratory Reserve Volume (IRV)**: The additional air that can be inhaled after a normal inhalation.
- **Expiratory Reserve Volume (ERV)**: The additional air that can be exhaled after a normal exhalation.
- **Residual Volume (RV)**: The amount of air remaining in the lungs after a maximal exhalation.
- **Inspiratory Capacity (IC)**: The maximum amount of air that can be inhaled after a normal exhalation (TV + IRV).
- **Vital Capacity (VC)**: The maximum amount of air that can be exhaled after a maximal inhalation (TV + IRV + ERV).

2. **Analyzing Each Statement**:
- **Statement (i)**: Inspiratory Capacity (IC) = Tidal Volume + Residual Volume
- This statement is **incorrect**. The correct formula for IC is TV + IRV.

- **Statement (ii)**: Vital Capacity (VC) = Tidal Volume (TV) + Inspiratory Reserve Volume (IRV) + Expiratory Reserve Volume (ERV)
- This statement is **correct**. It accurately defines vital capacity.

- **Statement (iii)**: Residual Volume (RV) = Vital Capacity (VC) - Inspiratory Reserve Volume (IRV)
- This statement is **incorrect**. The correct relationship is RV = VC - (TV + ERV).

- **Statement (iv)**: Tidal Volume (TV) = Inspiratory Capacity (IC) - Inspiratory Reserve Volume (IRV)
- This statement is **correct**. Rearranging the formula for IC gives us this relationship.

3. **Conclusion**:
- From the analysis, we find:
- Statement (i) is incorrect.
- Statement (ii) is correct.
- Statement (iii) is incorrect.
- Statement (iv) is correct.
- Therefore, the correct options are (ii) and (iv).

### Final Answer:
- The correct options are:
- (ii) Vital Capacity (VC) = Tidal Volume (TV) + Inspiratory Reserve Volume (IRV) + Expiratory Reserve Volume (ERV) (Correct)
- (iv) Tidal Volume (TV) = Inspiratory Capacity (IC) - Inspiratory Reserve Volume (IRV) (Correct)