Final answer:
Photosynthesis uses carbon dioxide to produce glucose, which serves as an energy source for plants and animals during cellular respiration.
Step-by-step explanation:
Photosynthesis takes carbon in from the atmosphere and uses it to form glucose, the energy source for all plants and animals to use in cellular respiration. During photosynthesis, carbon dioxide (CO₂) and water (H₂O) combine with solar energy to create glucose, a carbohydrate (C₆H₁₂O₆), and oxygen. Glucose, the main product of photosynthesis, is used as "food" by plants and converted into usable chemical energy, ATP, during cellular respiration. Oxygen, which is essential for animal life, is released as a waste product of the photosynthesis process.