Answer:
The sternum, thoracic vertebrae, and ribs protect the heart and lungs.
Step-by-step explanation:
The skeleton can be divided into the axial skeleton (the skull and the vertebral column), visceral skeleton (ribs and sternum) and the appendicular skeleton (extremities).
The function of the visceral skeleton is to support and protect the first portion of the digestive and cardio-breathing apparatus.
In mammals, the second part of the vertebral column (thoracic vertebrae), the ribs and the sternum delimitate a protective box for lungs and heart.