This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Back region, Subject name: Anatomy
Which veebral segment is numerically most constant? 
Select and explain. 
A. Cervical, B. Thoracic, C. Lumbar, D. Sacral
A: Cervical
Answer: A: Cervical 
Explanation: The number of veebrae in a region can vary but overall the number remains the same. The number of those in the cervical region however is only rarely changed.