Based on cellular mechanisms there are two major types of regeneration found in the animals . Which one of the following is the correct example of the type mentioned?

Options

A. Epimorphosis - Regeneration of crushed and filtered out pieces of a Planaria into as many new Planarians.
B. Morphallaxis - Regeneration of two transversely cut equal pieces of a Hydra into two small hydras
C. Epimorphosis - Replacement of old and dead erythrocytes by the new ones.
D. Morphallaxis - Healing up of a wound in the skin.

Answer

To solve the question regarding the types of regeneration in animals, we can break down the process step by step:

### Step-by-Step Solution:

1. **Understand the Types of Regeneration**:
- There are two major types of regeneration based on cellular mechanisms: **Morpholaxis** and **Epimorphosis**.

2. **Define Morpholaxis**:
- Morpholaxis refers to the regeneration process where lost body parts are replaced by remodeling the remaining tissue. This process involves little to no cellular proliferation.

3. **Define Epimorphosis**:
- Epimorphosis involves active cellular proliferation prior to the replacement of lost body parts. This means that cells divide and migrate to the injury site to facilitate regeneration.

4. **Identify Examples**:
- An example of Morpholaxis is **Hydra**, which can regenerate into two smaller hydras when cut.
- An example of Epimorphosis is **Planaria**, where neoblast cells proliferate and migrate to the injury site to form a regeneration blastema.

5. **Evaluate the Options**:
- Option 1: Incorrect - It misrepresents the regeneration process in Planaria.
- Option 2: Correct - It accurately describes Morpholaxis with Hydra.
- Option 3: Incorrect - It misrepresents the process of erythrocyte replacement.
- Option 4: Incorrect - It misattributes wound healing to Morpholaxis instead of Epimorphosis.

6. **Conclusion**:
- The correct answer is **Option 2**, which states that Morpholaxis involves the regeneration of two transversely cut pieces of Hydra into two smaller hydras.