Which of the following defines the phenomenon of dedifferentiation ?

Options

A. Lossing the capacity of division
B. Lossing the capacity of division after regaining the same
C. Regaining the capacity of division
D. All of these

Answer

To solve the question regarding the definition of the phenomenon of dedifferentiation, we can break down the concepts involved step by step.

### Step-by-Step Solution:

1. **Understanding Differentiation**:
- Differentiation is the process where a cell becomes specialized to perform a specific function. During this process, cells lose their ability to divide. For example, stem cells differentiate into specialized cells like muscle or nerve cells.

**Hint**: Remember that differentiation leads to specialization and loss of division capacity.

2. **Understanding Re-differentiation**:
- Re-differentiation refers to the process where a cell that has previously lost its ability to divide (after differentiation) regains that ability and then may lose it again to perform specialized functions.

**Hint**: Think of re-differentiation as a cycle of gaining and losing division capacity.

3. **Understanding Dedifferentiation**:
- Dedifferentiation is the process where specialized cells regain their ability to divide. This can occur under certain conditions, allowing cells that have become specialized to revert to a more primitive state where they can proliferate again.

**Hint**: Dedifferentiation is about going back to a state where cells can divide again.

4. **Analyzing the Statements**:
- The first statement refers to losing the capacity for division, which describes differentiation, not dedifferentiation.
- The second statement discusses losing the capacity for division and then regaining it, which describes re-differentiation.
- The third statement describes regaining the capacity for division, which accurately defines dedifferentiation.

5. **Conclusion**:
- Based on the definitions and analysis, the correct answer to the question is the third statement, which defines dedifferentiation.

### Final Answer:
The phenomenon of dedifferentiation is defined by the regaining of the capacity for division.