A neonate has a prominent defect at the base of this spine through which his meninges and spinal cord protrude. A failure of which the following processes is the most common cause of this type of defect?
(A)development of the body
(B)Development of the pedicle
(C) Development of primary vertebral ossification centers
(D)Development of the superior articular process
(E)Fusion of the vertebral arches
Answer: (E) Fusion of the vertebral arches