The answer is D, photosynthesis and respiration.
—Evidence—
Oxygen is a byproduct of photosynthesis and, correspondingly, carbon dioxide the byproduct of respiration.
Oxygen gives our cells the ability to break down food in order to get the energy we need to survive. Although other animals may use different organs to breathe with, they all get oxygen into their bodies through respiration.
<span>The means is unknown. Filoviruses are known for causing hemorrhagic fever in humans. However, once a human is infected, passing the virus from person-to-person is the means by which others become infected. Most especially is the transmission through infected bodily fluids or objects that have been unsterilized and come into contact with those fluids.</span>
Answer: Cyanobacteria, oxygen
Cyanobacteria also known as Cynophyta and blue green algae. It is a phyllum of bacteria that produces it's own food like plants by the process of photosynthesis. It is found in freshwater lakes, damp soils, oceans, moistened rocks and even in animal fur. The purple sulfur bacteria belongs to the group of Proteobacteria. It is an anaerobic bacteria. It is found in hot springs, and stagnant water. It is a photosynthesizing bacterial strain like Cyanobacteria but it does not utilize water to be reduced in the photosynthesis process like in Cynobacteria, to produce oxygen.
Hence, only the <u>Cyanobacteria</u> are capable of releasing <u>oxygen</u>.