The by-Product of Photosynthesis is (1) CO2 (2) H20 (3) Glucose (4) O2

Answer: option (4)

Explanation: The photosynthesis process is the process by which photosynthetic autotrophs convert light energy into chemical energy that can later be used to power the activity of living organisms. 

The three key elements required for the photosynthetic process are water, carbon dioxide and light. 

The resulting product is stored in the form of sugar made from water and carbon dioxide. A by-product of the photosynthetic process is oxygen.

6CO2 + 6H2O → C6H12O6 + 6O2