Answer:
Sunlight
Explanation:
Photosynthesis is the process where by plants manufacture their own food through conversion of carbon(iv)oxide and water in presence to sunlight to produce glucose and oxygen as by product.
The reaction is photo-catalyzed and would only take place in the presence of sunlight.
6CO₂ + 6H₂O + sunlight → C₆H₁₂O₆ + 6O₂
