Inspiratory reserrve volume is the volume of air which can be inspired in addition to the normal inspiration.

Answer

**Step-by-Step Solution:**

1. **Understanding Inspiratory Reserve Volume (IRV):**
- Inspiratory Reserve Volume refers to the additional amount of air that can be inhaled after a normal inhalation (tidal volume).
- It is the volume of air that can be inspired beyond the tidal volume during deep breathing.

2. **Defining Tidal Volume:**
- Tidal Volume is the amount of air that is inhaled or exhaled during a normal breath.
- For males, the tidal volume is approximately 500 ml, while for females, it is around 400 ml.

3. **Calculating Inspiratory Reserve Volume:**
- The Inspiratory Reserve Volume is the difference between the total lung capacity and the sum of tidal volume and expiratory reserve volume.
- In males, the Inspiratory Reserve Volume is about 3000 ml.
- In females, the Inspiratory Reserve Volume is approximately 2100 ml.

4. **Conclusion:**
- The statement "Inspiratory reserve volume is the volume of air which can be inspired in addition to the normal inspiration" is true.
- This means that IRV is indeed the extra air that can be inhaled after a normal breath.