Final answer:
The abdominal cavity provides the least protection to its internal structures compared to the cranial cavity well-protected by the skull or the thoracic cavity shielded by the rib cage.The correct answer is c. endocrine.
Step-by-step explanation:
The body cavity which provides the least protection to its internal structures is the abdominal cavity.
The abdominal cavity is a part of the ventral cavity that lies directly below the thoracic cavity and is separated by the diaphragm.
Unlike the cranial cavity that houses the brain and is well-protected by the skull, or the thoracic cavity protected by the rib cage, the abdominal cavity only has the muscular abdominal wall and is thus more susceptible to injury.
It contains vital organs such as the stomach, liver, and intestines, which are not protected by bone like the heart or lungs which have the rib cage, or the brain which is encased in the skull.
As for the protection features of the body, the cranial cavity contains a component of the central nervous system and is surrounded by the skull bones.
The vertebral column protects the spinal cavity.
It's important to note that not all body cavities must open to the outside world.
The fluid that protects the brain and spinal cord is the cerebrospinal fluid.
Lastly, the body cavities such as the nose, mouth, and others that are exposed to the external environment are lined by the mucosa.
The correct answer is c. endocrine.