You're misunderstanding a bit. Here are some definitions from Wikipedia, where I added some bold for emphasis:
Expiratory reserve volume: the maximal volume of air that can be
exhaled from the end-expiratory position
Inspiratory reserve volume: the maximal volume that can be inhaled
from the end-inspiratory level
In plain terms, ERV is how much you can ...
The number of stomata on the leaf is the limiting factor. Light causes the stomata to open, more so with increasing light intensity. Once all the stomata are fully open, the transpiration rate rate cannot increase any further (for a given set of temperature and relative humidity conditions).
The factors limiting ATP production are the rate of fuel (glucose, fats, amino acids, etc.) metabolism and its efficiency (ATP molecules per fuel molecule).
It is possible to produce ATP with zero oxygen by the glycolytic pathway; if this were not true, there would be no anaerobic organisms on Earth (which there clearly are). Muscle can do this too for short ...