Because it is flexible. Think about it; the ribs protect both the lungs and the heart. If the ribs were solid bone all the way around then unless you constantly break your ribs you wouldn't be able to expand the cheat to breath. Additionally your lungs would constrict the heart to a degree that it would function properly.
Answer:
C. james-lange theory............
"I like what you did when you presented the slideshow! It brought a smile to my face!"
Answer
Explanation: any ways lets get to the answer there is your answer