Вставим слова в текст:
Your 1brain is a very important part of your body. You use it to think and it sends messages to all the other parts of your body. It tells your 2heart to work, so the red 3blood can go around your body. You also have lots of strong white 4bones inside your body, so you can stand up. The 5muscles hold them together and they make them move, so you can run and walk.
Ответ: brain, heart, blood, bones, muscles