Answer:
A. Cyanobacteria.
Explanation:
Both cyanobacteria and plants use water as an electron donor for the light phase of photosynthesis and make ATP and NADPH. The ATP and NADPH are used in the Calvin cycle to fix the atmospheric CO2 into glucose. The use of water as an electron donor releases oxygen gas as a by-product. This photosynthesis wherein the use of water as an electron donor releases oxygen gas as a by-product is also called oxygenic photosynthesis.
Plant uptake is the process which converts inorganic phosphorus in a rock to an organic form of phosphorus.
The soil on the valley floor because it would not have runoff. Hope this helps.