<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 red blood cells? Context: Red blood cells main function is to transport oxygen and remove carbon dioxide. Answer: [/INST]The main function of red blood cells is to carry oxygen from the lungs to the body's tissues and remove carbon dioxide.</s>