The inability of a viable seed to germinate due to internal conditions though external conditions are suitable is called as

Options

A. seed dormancy
B. quiescence
C. silence
D. senescence

Answer

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks about a specific term that describes the inability of a viable seed to germinate when external conditions are favorable, but internal conditions prevent germination.

2. **Identifying Key Terms**: The key terms in the question are "viable seed," "germinate," "internal conditions," and "external conditions."

3. **Defining Germination**: Germination is the process by which a seed develops into a new plant. It requires suitable external conditions such as moisture, temperature, and light.

4. **Understanding Dormancy**: Dormancy refers to a state in which seeds are alive but not actively growing. In this state, seeds do not germinate even when conditions are right. This is due to internal factors such as seed coat hardness, hormonal balance, or the presence of inhibitors.

5. **Differentiating Terms**:
- **Quiescence**: This is a state where seeds are not germinating due to unfavorable external conditions.
- **Senescence**: This refers to the aging process in plants, not applicable here.
- **Cauchy Stage**: This term refers to the suspended growth of the embryo, which is not the same as dormancy.

6. **Conclusion**: Since the question specifies that the seed is viable and the external conditions are suitable, but the seed cannot germinate due to internal conditions, the correct term is **seed dormancy**.

**Final Answer**: The inability of a viable seed to germinate due to internal conditions, though external conditions are suitable, is called **seed dormancy**.

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