Read the headings in the text. What causes these to happen?

The headings in the text are Yawn, Blush, Hiccup, Sneeze, Cough, Snore. These are all involuntary bodily functions. The text goes on to explain what causes each of these to happen. Yawning is caused by tiredness or boredom. Blushing is caused by embarrassment. Hiccups are caused by irritation of the diaphragm muscle. Sneezing is caused by irritants in the nose, such as dust, pollen, or a virus. Coughing is caused by irritations in the airways, throat, and lungs. Snoring is caused by the vibration of parts of the mouth and throat when air cannot move freely through the mouth or nose.