Question

Vertebrae central of reptiles are
(A) Homocoelous
(B) Heterocoelous
(C) Amphicoelous
(D) Procoelous

Answer 1

In the vertebrate spinal section, each vertebra is an uneven bone with a complex structure comprised of bone and some hyaline cartilage, the proportions of which vary according to the column of the backbone and the species of vertebrate.

Complete answer:
Option (A) Homocoelous
This is the incorrect option
Option (B) Heterocoelous
Heterocoelous vertebrae have saddle-shaped ends. Heterocoelous has a central concave on one axis and convex on the other. They fit jointly like one saddle placed upside beneath at ninety degrees on top of another. This is one of the most adaptable of vertebral joints and is found in the free vertebrae of birds, especially in the neck.
Option (C) Amphicoelous
The vertebrae are meant to be amphicoelous when they have biconcave, or depressed on both the anterior and posterior sides, but, if it mineralizes or ossifies, the vertebrae are termed opisthocoelous which means bulged on the anterior side and depressed on the posterior side. In amphicoelous vertebrae both the surfaces are concave and it permits some motion across a broad range of paths. These are found in fishes, pods, and some urodele.
Option (D) Procoelous
The procoelous vertebrae have a concavity to the anterior end but not the posterior. Organism under the procoelous vertebrae comprises the frogs and most of the reptiles. Opisthocoelous group is the opisthocoelous vertebrae that are concave at the posterior end but not the anterior end. Most salamanders are of the opisthocoelous type.

This the correct answer is option (D) Procoelous.

Note: The central portion of a vertebra is called the centrum. The morphology of the anterior and posterior faces of a centrum, where it articulates with other vertebral bodies, somewhat specifies the flexibility and strength of the vertebral column.