Which of the following has the odontoid process?
A. 7 th vertebra of Frog
B. Second vertebra of Frog
C. Second cervical vertebra of mammal
D. Second thoracic vertebra of mammal

Hint: In mammals including human beings there are seven vertebrae of the vertebral column which constitute the cervical vertebrae. These are small sized vertebrae.

Complete answer:
-There are a total of seven cervical vertebrae present in the body and these are present in the neck region. The first vertebra is known as atlas and the second is known as axis. 1, 2, 7 are atypical vertebrae and 3,4,5 and 6 are main vertebrae.
-The atlas guides the head and it constitutes a ring of bone. The atlanto-occipital joint is a joint which is composed by the articulation of atlas and condoles the occipital bone and by this joint movement of head is easy..
-The second cervical vertebrae is the pivot on which atlas turns in the rotary movement of the head. From the body of the axis a process of bone rises which is called an odontoid peg which articulates with the back of the anterior arch of the atlas. The atlas moves to the odontoid peg of the axis, and gives a pivot joint for the head rotates.
-The seventh cervical vertebrae are the first vertebrae with an unflagged prickly process and have a tubercle in the tip. It makes a different projection in the neck and can be viewed in the lower part of the neck.
-In humans the second cervical vertebra of the spine by the atlantoaxial joint forms a pivot upon which the first vertebra carries the rotation of the head.
-One of the important characteristics of second cervical vertebrae is a strong odontoid process known as den which rises from the upper surface of the body.
-The Odontoid process is a projection of the axis, a second cervical vertebra and joins the main body of the vertebra.

Hence, the correct answer is option (C).

Note: From the movement of the head and neck, the first three cervical vertebrae are very crucial. The sensation for the upper part of the head is controlled by the C2, whereas the front and back parts of the head are controlled by the C3.