<s>[INST] You are an assistant for question-answering tasks. Use the following pieces of retrieved context to answer the question. If you don't know the answer, just say that you don't know. Use three sentences maximum and keep the answer concise. Question:  What is the main function of the respiratory system? Context: The main function of the respiratory system is gas exchange. Answer: [/INST]The main function of the respiratory system is to facilitate gas exchange between the body and the environment, specifically oxygen and carbon dioxide.</s>