Multiple choice Hiccups are due to the activity of intercostal muscles food in air tract diaphragm inadequate oxygen in atmosphere Reveal answer Fill a bubble to check yourself C Correct answer Explanation Hiccups are due to the involuntary contraction of the diaphragm. Hiccups may occur individually, or they may occur in bouts. The rhythm of the hiccups, or the time between hiccups, tends to be relatively constant.