Assertion: When simultaneously exposed to light of both red and far red wavelengths, the rate of photosynthesis is far higher than the sum of the red light and far red light photosynthesis rates.
Reason: Two photosystems, processing different wavelengths, cooperate in photosynthesis.

1. Both assertion and reason are true and the reason is the correct explanation of the assertion.
2. Both assertion and reason are true but the reason is not the correct explanation of the assertion.
3. Assertion is true but reason is false.
4. Both assertion and reason are false.

What conclusion can be drawn from the finding that while some bacteria have only photosystem I, cyanobacteria have both?
1. Photosystem II was lost in some species as it was selected against by the nature.
2. Photosystem I must be more ancestral.
3. Photosystem II may have evolved to be more photoprotective.
4. Cyclic photphosprolylation is more important than non cyclic photophosphorylation.