Answer:
Cellular Respiration:
C6H12O6 + 6O2 → 6CO2 + 6H20 + energy (Glucose + Oxygen yields Carbon Dioxide + Water + Energy)
Photosynthesis is important to living organisms because it is the number one source of oxygen in the atmosphere. Without photosynthesis, the carbon cycle wouldn't occur/exist, oxygen-requiring life would not survive and plants would die. Without photosynthesis there would be little to no oxygen on the planet and Earth would be impossible to live on.