How might we be able to increase plant production?...

[mariposa]

in plants it is possible that the cyclic electron pathway is only used when co2 is limited, so how might we be able to increase plant production????

1- add water
2- add oxygen in an airtight greenhouse
3- add photosynthetic bacteria
4- increase sunlight

And i been having problems getting the correct option in this one:,

biologists are certain that oxygen was built up in the atmosphere by the invention of photosynthesis.The appereance of oxygen and therefore the beginning of extensive aerobic life was made possible by the appereance of:

1- fermentation
2- photosystem I
3- photosystem II
4- glycolisis
5- the nucleos



NEED SOME HELP

[mith]

Which process produced oxygen(water splitting)?