Which one of the following statements is totally wrong about the occurrence of the notochord, while the other three are correct?
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It is present only in larval tail in Ascidians
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It is replaced by a vertebral coloumn in adult frog
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It is absent throughout life in humans from the very beginning
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It is present throughout life in Amphioxus
C.
It is absent throughout life in humans from the very beginning
The notochord is a flexible, rod -shaped body found in the embryo of all chordates. It is composed of cells derived from the mesoderm. It represents the primitive axis of the embryo. In some chordates, it persists throughout life as the main axial support of the body (e.g. Amphibians), while in most vertebrates including humans it becomes the vertebral body of the vertebral column.
