Explain with the help of labelled diagrams the development that takes place in each of the body parts of a Planaria where body is cut into three pieces. None this process and give an example of an organism in which a similar process can be observed.

Planaria can be cut into any number of pieces and each piece grows into a complete organism. This process is called regeneration. Regeneration is carried out by specialised cells.

When a Planaria is cut into three pieces, each of its pieces grow into separate individual; specialized cells proliferate; mass of cells get differentiated into various cells and tissues.
Another example of an organism showing the characteristics is Hydra. Diagram: