Final answer:
The cranium is the rigid structure that houses and protects the human brain. It is made up of eight cranial bones forming the cranial cavity. The mandible, maxilla, and sternum are not associated with enclosing the brain.
Step-by-step explanation:
The human brain is housed within a rigid structure called the cranium. The skull is the part of the human skeleton composed of cranial and facial bones, with the cranium specifically designed to protect the brain and house the middle and inner ear structures. It is made up of eight cranial bones: the frontal bone, two parietal bones, two temporal bones, the occipital bone, the sphenoid bone, and the ethmoid bone. These bones form the cranial cavity, providing a sturdy case that ensures the delicate tissues of the brain remain safeguarded from external forces.
The other options provided, such as the mandible, maxilla, and sternum, are distinct skeletal structures. The mandible, or lower jawbone, and the maxilla, or upper jawbone, are part of the facial bones. Meanwhile, the sternum, commonly referred to as the breastbone, is a long flat bone at the center of the chest and is not associated with housing the brain.