Final answer:
The final product of photosynthesis is glucose, which is a stable chemical that can store energy long term in the form of large carbohydrate molecules such as starch.
Step-by-step explanation:
The final product of photosynthesis, a stable chemical that stores energy long term, is glucose. Glucose is a simple sugar molecule that can be used to store energy in the form of large carbohydrate molecules such as starch.
The energy captured and stored by photosynthesis in glucose can last for hundreds of millions of years.