Answer:
C. Photosynthesis and cellular respiration
Step-by-step explanation:
Photosynthesis uses energy from the sun, carbon dioxide, and water, to produce glucose and oxygen. This is used as a food source in plants.
Glucose is broken down by cellular respiration to release energy in the form of ATP.
Cellular respiration breaks down glucose in the presence of oxygen to produce energy, releasing water and carbon dioxide.
So the reactants and products are switched for these two processes and they could be considered "opposites" of one another.