This happens when a detection is accomplished through heuristics. There is no such thing as a heuristic virus. As a technical concept, everything in malware detection is done via heuristics.
Photosynthesis is the process in which plants (also autotrphoic protists and some bacteria) use light energy, from the Sun, to make sugars and organic food molecules from CO2 and water (H2O). This process is essential for the formation of not only energy, but also for the formation of glucose for purposes of structure.
Photosynthesis, a process undergone by the chloroplasts of the cells of plants, captures the light energy radiated by the sun and utilizes it for the synthesis of glucose from carbon dioxide and water. A byproduct of this synthesis, oxygen (O2), is filtered out of these plants and into the surrounding atmosphere. Animals then inhale this oxygen and, using it and water, perform cellular respiration to extract energy from food in the form of ATP (Adenosine triphosphate).