Final answer:
Cellular respiration and photosynthesis both recycle carbon dioxide and oxygen, with one process using the byproducts of the other as reactants, thus sustaining the carbon cycle and providing energy to living organisms.
Step-by-step explanation:
Cellular respiration and photosynthesis contribute to recycling reaction products by functioning in a biological cycle where they use and produce the same substances. Specifically, photosynthesis consumes carbon dioxide and produces oxygen, while cellular respiration consumes oxygen and produces carbon dioxide. These two processes are interdependent; the products of one process serve as the reactants for the other, which is evident through their contributions to the carbon cycle.
Moreover, photosynthesis absorbs light energy to build carbohydrates in chloroplasts, utilizing carbon dioxide and water as raw materials. Conversely, aerobic cellular respiration releases energy by metabolizing carbohydrates using oxygen to break them down, which occurs in the cytoplasm and mitochondria. This illustrates how these processes support life on Earth by recycling vital elements like oxygen and carbon dioxide.
In summary, cellular respiration and photosynthesis serve as integral components of the carbon cycle, ensuring the continuous recycling of oxygen and carbon dioxide while furnishing energy to living organisms. Thus, the correct answer is that they both recycle carbon dioxide and oxygen.