Name the labeled parts a, b in the diagram given below :

The diagrammatic sketch given below represents a hypothetical chordate. a) If you find any mistake in the labelled parts, copy the diagram and make necessary corrections in the labeling. b) Based on any two labelled parts in the diagram, mention how this phylum differs from nonchordates.

Observe the figure of Nostoc given below a. In which kingdom it belongs ? B.Name the part labelled as "A" in the figure and give its function.

Name the parts A, B, C, D.