These volumes are needed when there is suspicion of restrictive pattern, which can be presented along with obstructive pattern with FVC < 80%.

All volumes are measured in litres.

Yes. ----

The main differences in lung volumes are related more to the size differences between the average man and woman and thoracic cavity dimensions. If a man and a woman have similar size, stature, and thoracic dimensions, there should be little difference in their lung volumes.

These volumes are needed when there is suspicion of restrictive pattern, which can be presented along with obstructive pattern with FVC < 80%.

Repiratory volumes are used in research to determine the effects of disease and lifestyle habits on lung capacity.

In medicine, spirometry can be used to diagnose asthma as well as other lung conditions. It can be used to gauge whether treatements for these conditions are working.