In this section, each item consists of six sentences of a passage. The first and sixth sentences are given as SI and S6. The middle four sentences in each have been jumbled up and labelled as P, Q, R and S. You are required to find the proper sequence of the four sentences and mark your response accordingly.

S1: Many fully differentiated organisms have the ability to give rise to new individual organisms from their body parts.  
P:  For example, simple animals like Hydra and Planaria can be cut into any number of pieces and each piece grows into a complete organism.  
Q: That is, if the individual is somehow cut or broken up into many pieces, many of these pieces grow into separate individuals. 
R: This is known as regeneration.
S: Regeneration is carried out by specialised cells.
S6: These cells proliferate and make large numbers of cells.