The process that does the opposite of photosynthesis is cellular respiration. Here's a breakdown of how they are opposite:

Photosynthesis:

* Inputs: Carbon dioxide (CO₂), water (H₂O), sunlight

* Outputs: Glucose (C₆H₁₂O₆), oxygen (O₂)

* Purpose: To convert light energy into chemical energy stored in glucose.

Cellular Respiration:

* Inputs: Glucose (C₆H₁₂O₆), oxygen (O₂)

* Outputs: Carbon dioxide (CO₂), water (H₂O), energy (ATP)

* Purpose: To break down glucose to release energy (ATP) for cellular processes.

In essence, photosynthesis takes in CO₂ and H₂O and uses light energy to create glucose and O₂. Cellular respiration takes in glucose and O₂ and breaks them down to produce CO₂ and H₂O, releasing energy in the process.

These two processes are essential for life on Earth, forming a cycle where energy is transferred and transformed.