Question 1 Describe briefly regeneration in hydra?
The process of getting back a full organism from its body part is called regeneration.
For Example : Hydra, planaria (flatworm)
Regeneration is carried out by specialised cells.
These cells increase in number very quickly and make large number of cells. From this mass of cell, different cells undergo changes to become various cell types and tissue. These changes take place in an organised sequence called as development. These tissue form various organs and body parts. This mode can be used to produce only those organism which have relatively simple body organisation consisting of only few specialised cells or tissue.