Final answer:
The cervical vertebrae (C1-C7) have the greatest range of motion for rotation in the vertebral column. This flexibility is due to the unique structure of the cervical vertebrae, which allows for a higher degree of movement in the neck compared to the thoracic, lumbar, and sacral regions.
Step-by-step explanation:
If a student asked which spinal curve is labeled "E", it would depend on the provided illustration or context that is not given here. However, I can address the question regarding which region of the vertebral column has the greatest range of motion for rotation. The answer is: a. cervical.
The cervical vertebrae (C1-C7) allow for a great range of motion, including rotation, due to their shape and the flexibility of the neck. The large range of motion in the cervical region contrasts with other regions such as the thoracic, lumbar, and sacral curves, which have different roles and degrees of movement.
The thoracic vertebrae are more rigid due to the connection with the ribs and provide less rotation compared to the cervical vertebrae. The lumbar vertebrae, while allowing for flexion and extension, also have a limited rotation range. The sacrum, formed by the fusion of sacral vertebrae, is largely immobile due to its role in connecting the spine to the pelvic hips.