How does photosynthesis relate to all living organisms?

It is the process that fixes inorganic carbon into a form all living organisms can use. This makes photosynthesis the entry point for all biological chemical energy. 

Photosynthesis uses the solar energy and converts this to chemical energy bound, finally, in the fixed carbon in organic glucose molecules. 
Organic can be recognized as having carbon bound with hydrogen. 

CO2 + H20 => glucose (CH2O)6
Hope this helps!
~{Dunsforhands}

Animals and plants both synthesize fats and proteins from carbohydrates; thus glucose is a basic energy source for all living organisms.


CO2 + H20 => glucose (CH2O)6