Hello there!
'Parental generation' is the term which he used. Hope I helped.
I think it's the first and second option but I could be wrong because I don't know much about deserts :)
Answer:
The byproducts cause the released of high concentration in the fermentation acids and the deceases in the level pf PH. It basically leads to inhibition of the growth of many bacteria. The toxicity at low PH value of the fermentation acids traditionally defined the uncoupling mechanisms. The fermentation acid are resistant bacteria with low PH and It able to generated the ATP and groe the low PH intracellular.
If CO2 was in very small amounts then it would be the limiting factor of photosynthesis, this means the process will take place at a much slower rate because it is lacking one of the raw materials it needs for the process to occur. To find the optimum light intensity you really need all other factors to be at optimum levels or in abundance.