The number of true ribs in humans is ........ . (in $pairs$)

The bone labeled $P$ in the given image is formed by the fusion of how many vertebrae?

Nucleus pulposus is found in

Which of the following statements are correct with reference to the human endoskeleton?
$A$. Human skull is monocondylic.
$B$. The joint between any two adjoining vertebrae is a cartilaginous joint.
$C$. In human beings, the number of cervical vertebrae is seven.
$D$. All ribs except the last $2$ pairs are bicephalic.
$E$. The occipital bone of the skull is articulated with the atlas vertebra.
Choose the correct answer from the options given below:

Through which aperture does the spinal cord pass out of the cranium?

Which of the following is the correct order of arrangement of the vertebral column from the head to toe?