In anatomy, the notochord is a flexible rod formed of a material similar to cartilage. If a species has a notochord at any stage of its life cycle, it is, by definition, a chordate. The notochord lies along the anteroposterior ("front to back") axis, is usually closer to the dorsal than the ventral surface of the animal, and is composed of cells derived from the mesoderm.
The short sequences of characters that appear and can be
seen at the end of a filename preceded by a period is filename extensions. While
a sequence structure is a set of statements that execute in the order they
appear.
