Answer:
Axial.
Explanation:
Surface anatomy is associated with the studying the external or outer features of an animal body that are visually configured. In respect to surface anatomy, 'axial' is associated to the formations alongside the body's center line. Such a body structure(axial) comprises of the central elements of a body like thorax, head, pelvis, abdomen, etc. that runs straight to the axis(center of the animal body) except the limbs. Thus, 'axial' is the correct answer.