Question

Regeneration occurs in:

• A. Planaria, but not in Hydra
• B. Hydra, but not in Planaria
• C. Paramecium, but not in Hydra
• D. Hydra and Planaria

Hint:

Hydra and Planaria are model organisms commonly studied for their strong regenerative powers.

Answer 1

The Correct Option is D

Both
Hydra and
Planaria possess remarkable regenerative abilities that enable them to regrow lost or damaged body parts. 1.
Hydra:

Hydra is a simple freshwater organism belonging to the phylum Cnidaria.
It can regenerate its entire body from a small piece of tissue due to the presence of specialized stem cells.
This regeneration process includes the formation of new tentacles, mouth, and body structure, essentially allowing the organism to develop into a fully functional new Hydra.
2.
Planaria:

Planaria is a flatworm from the phylum Platyhelminthes, well known for its exceptional regeneration capabilities.
If a Planaria is cut into several fragments, each fragment has the ability to regenerate into a complete organism.
This is possible because of the presence of pluripotent stem cells called neoblasts distributed throughout its body, which can differentiate into various cell types.
3.
Paramecium:

Paramecium is a unicellular protozoan and does not exhibit regeneration in the same sense.
While Paramecium can repair minor cellular damage and reproduce asexually by binary fission, it cannot regenerate lost parts or grow into a new organism from fragments.
In summary, Hydra and Planaria demonstrate impressive regenerative abilities, allowing complete body regeneration from small pieces, whereas Paramecium does not show such regenerative capacity.