Whether you are a smoker or a nonsmoker, you should take measures to protect your lungs. You can test your lung capacity by holding a lighted match about six inches from your face and trying to blow it out with your mouth wide open. If you cannot blow out the flame, arrange for a medical examination. Using a simple machine called a spirometer, a doctor can measure the lungs' strength and capacity. In other words, he can test how efficiently you breathe. When combined with a complete physical examination, the spirometer test may detect early signs of respiratory problems.

Q. Circle the outline which illustrates the structure of this paragraph and underline the topic sentence: ▼ ▲ ♦ ▊.