Question

From which embryonic structure, the vertebral column develops?
A. Neural canal
B. Archenteron
C. Notochord
D. Blastocoel

Answer 1

Hint:-Phylum Chordata includes three sub-phylum: Urochordata, Cephalochordata, and Vertebrata. Having a vertebral column is a characteristic feature of Vertebrates. All vertebrates are chordates, but all chordates are not vertebrates.

Complete step-by-step solution:-
The notochord is an elastic rod-like structure present in the embryonal stage of all chordates. Notochord contains many glycoproteins and other structural molecules which form a ring-like structure and provides elasticity and strength to the notochord.
In Vertebrates, the notochord is later replaced by a cartilaginous structure called the vertebral column. The vertebral column is grown surrounding the spinal cord, thereby protecting it. The notochord in vertebrates gets converted into a cushion-like disc which protects vertebrae from smashing. The notochord is fully replaced in the spine by the age of 4 in human beings.
Thus the correct option is (C) Notochord.

Additional information:- As the notochord has a strong structure, it becomes useful for the muscles to get attached to it. In many small fishes, muscles get attached to it and it helps their body to swim easily. Even in large fishes, it provides enough strength to muscles to get attached. Vertebrates have a spine which further increases the rigidity of the notochord.
Notochord also secretes some proteins that initiate organ formation through a process called organogenesis.

Note:-
Neural canal is the central portion (cavity or system of cavities) of the neural tube present in the embryo which gives rise to ventricles of CNS (brain and spinal cord). It contains the spinal cord.
Archenteron is the rudimentary alimentary canal formed during the gastrulation stage of an embryo.
Blastocoel, also known as blastocyst cavity, is a fluid-filled cavity present in the blastula.