Answer:
Photosynthesis can increase the pH level of the water and the reason is because it removes carbon dioxide that is present in the water.
Step-by-step explanation:
Photosynthesis is a chemical process/cycle that is executed by plants by consuming carbon dioxide and releasing oxygen into the air or water.
The photosynthesis can cause the pH level of the water to rise because of the removal of carbon dioxide from the environment.
I hope this answer helps.