Which of the following acts as a natural barrier to protect the lungs?

The rib cage is a bony structure in the thorax that protects vital organs like the heart, lungs, and other major vessels while also serving as a framework for breathing. It is composed of the thoracic vertebrae, ribs, and sternum.

The rib cage is the main organ for respiratory function and acts as a natural barrier to protect the lungs against injury and infection. It protects the lungs from being squished and provides a space for the lungs to expand.

Cranium refers to the part of the skull that encloses the brain. The sternum, also known as the breastbone, is a flat bone in the centre of the thorax. It connects to the rib bones on either side of the body, forming the front part of the rib cage. The femur is the longest, largest, and most powerful bone in the human body. It runs from the hip to the knee and bears the body's weight.