Living differentiated cells which have otherwise lost the capacity to divide, can region the power of division under certain conditions. This phenomenon is termed as

Options

A. differentiation
B. dedifferentiation
C. redifferentitation
D. development

Explanation

To solve the question, we need to identify the phenomenon where living differentiated cells, which have lost the ability to divide, can regain that ability under certain conditions. Let's break down the options provided in the question step by step.

### Step-by-Step Solution:

1. **Understanding Differentiation**:
- Differentiation is the process by which unspecialized cells (like those in the root and shoot apical meristems) mature into specialized cells that perform specific functions. This process does not involve regaining the ability to divide; rather, it is about cells becoming specialized.

**Hint**: Differentiation is about cells maturing to perform specific functions, not regaining division.

2. **Understanding De-differentiation**:
- De-differentiation refers to the process where mature, specialized cells lose their specific characteristics and regain the ability to divide. This is the key concept we are looking for, as it directly addresses the regaining of division capacity.

**Hint**: De-differentiation is when mature cells regain the ability to divide.

3. **Understanding Re-differentiation**:
- Re-differentiation occurs after de-differentiation, where the cells that have regained the ability to divide may again lose that ability and become specialized once more. This process does not fit the description of regaining division capacity.

**Hint**: Re-differentiation is about cells becoming specialized again after having divided.

4. **Understanding Development**:
- Development is a broader term that encompasses the changes an organism undergoes throughout its life cycle. It does not specifically refer to the ability of differentiated cells to regain division.

**Hint**: Development refers to the overall life cycle changes of an organism, not just cell division.

5. **Conclusion**:
- Based on the definitions and explanations above, the correct answer to the question is **de-differentiation**, as it specifically describes the phenomenon where differentiated cells regain their capacity to divide under certain conditions.

### Final Answer:
The phenomenon is termed as **de-differentiation**.