Which of the following animals can be cut into any number of pieces and each piece grows into a complete organism?
I. Hydra
II. Planaria

Correct option is B

Ans. (B) Both I and II

Explanation:

Both Hydra and Planaria have remarkable regenerative abilities. If these animals are cut into pieces, each piece can grow into a complete organism through the process of regeneration.

• Hydra: A small, simple freshwater organism that can regenerate from almost any part of its body. Even small fragments can regenerate into a whole new organism.

• Planaria: A type of flatworm that has the ability to regenerate its entire body from even a small fragment. If cut into pieces, each piece can grow into a full, functional organism.

Information Booster:

• Regeneration: The process by which organisms replace lost or damaged parts of their bodies. Some animals, like Hydra and Planaria, can regenerate entire new organisms from pieces of their bodies.

• Other Examples of Regeneration:

  • Starfish and some species of lizards can also regenerate lost body parts.

• Hydra's Unique Ability: Hydra can regenerate due to its high cellular plasticity, meaning its cells can easily transform into various types needed for regeneration.

• Planaria's Regeneration Mechanism: Planaria's regenerative abilities are due to the presence of stem cells called neoblasts, which allow regeneration of tissues and organs.