Answer:
Water (H2O)
Explanation:
Light reactions of photosynthesis release oxygen as a by-product. In the presence of sunlight, photolysis of water molecules occurs. Splitting of two water molecules obtains four electrons, four protons, and molecular oxygen. The oxygen-evolving complex, also called the water-splitting complex is associated with photosystem II (PS II). Splitting of water occurs in the oxygen evolving complex and the released electrons are passed one at a time to the reaction center of PS II. Therefore, a water molecule serves as a source of oxygen released during photosynthesis.
Colonies of cyanobacteria benefit aquatic organisms because they can be an important source of food to organisms.
The problem with cyanobacteria is that they can be harmful and in an alga bloom then can cover the surface cutting off any light to other plants and producing toxins that kill fish and other life forms.
your answer would be c) iron deficiency
Lactic acid fermentation is the by-product of B. Anaerobic glycolysis. When oxygen is not readily available, organisms such as humans switch from aerobic respiration to lactic acid fermentation which is an anaerobic process that produces two ATP for every glucose molecule broken down in the glycolytic pathway.