Main & most obvious reason - lack or absence of sunlight. Other external factors include not enough carbon dioxide and ambient temperatures that are too hot or too cold.
There could also be other factors such as a genetic disorder in plants that cause a lack of chlorophyll If the soil type is incorrect, or the water content incorrect, normal processes within the organism will not occur
Cutting off a plant's light supply will eventually cause photosynthesis to stop. The plant will continue to produce oxygen for a while after.
without sunlight as an energy, phosynthesis cannot occur
This is a member of the normal microbiota for most people, and it is difficult to prevent contact with it.
Cutting the stem of hydrilla underwater can prevent air bubbles blocking the xylem.
Human or some other animal activity that stops the natural flow of an ecosystem and alters its outcome
If oxygen were not produced during photosynthesis then organisms could not perform cellular respiration. This means that they couldn't produce carbon dioxide which would make the plants unable to undergo photosynthesis.
Brain cells
boil it in water then put it in ethanol then put iodine on it the leave will tiurn dark if photosynth is occurring
Photosynthesis.
How can temperature either help fusion to occur or prevent fusion from occurring?
Photosynthesis is the process
No. There is no way for us to prevent tornadoes. We cannot control nature.
Sometimes you can prevent conflicts by walking away from the conflict.
Contraceptives are used to prevent pregnancy from occurring.
Two common examples are photosynthesis and cellular respiration.
You can't stop them from occurring, you just have to learn to deal with them by being better prepared.
No. Currently there is no way to prevent earthquakes from occurring.
A pap smear test won't prevent pregnancy.