Multiple choice

Breathing starts with a dome-shaped muscle at the bottom of the lungs called _____.

  1. intercostals muscle

  2. ribcage

  3. diaphragm

  4. sternum

Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The diaphragm is a dome-shaped muscle located at the base of the chest cavity that contracts and relaxes to facilitate breathing. The ribcage protects the lungs but is made of bone, not muscle.