Question

Regeneration of $Hydra$ is

• A. Epimorphosis by glandular cells
  
• B. Epimorphosis by archaeocytes
  
• C. Morphallaxis by interstitial cells
  
• D. Epimorphosis by interstitial cells
  

Answer 1

The correct option is C Morphallaxis by interstitial cells


Morphallaxis :
The process in which a fragment can regenerate the whole body of an organism is called morphallaxis.
Examples: Formation of a whole organism from a fragment by $Hydra,Planaria$ and $Amoeba$.
1) Regeneration of transverse or longitudinal cut pieces of Hydra into complete $Hydra$. The lost parts are regenerated by the interstitial cells in $Hydra$.
2) Regeneration of complete worm from cut fragments of Planaria.

Epimorphosis :
The process of replacement or regeneration of lost body parts by cell proliferation of somatic cells followed by cell differentiation is called epimorphosis.
Examples:
1) Regeneration of tail or limb in Salamander.
2) Regeneration of intestine or alimentary canal in Sea cucumber after ejection of internal organs.
3) Regeneration of tail by lizards after self-amputation (autotomy).
4) Regeneration of injured arms of starfish.

Final answer :
(A) Morphallaxis by interstitial cells