Which of the following breaks the dormancy of seeds?

Options

A. Cytokinin
B. `GA_(3)`
C. Ethylene
D. All the above

Answer

To determine which of the given options breaks the dormancy of seeds, we need to analyze each option provided in the question.

### Step-by-Step Solution:

1. **Understand Seed Dormancy**: Seed dormancy is a period during which seeds are inactive and do not germinate, even under favorable conditions. Breaking this dormancy is crucial for seed germination.

2. **Evaluate the First Option - Cytokinins**:
- Cytokinins are plant hormones that promote cell division and growth.
- While they play a role in various growth processes, they are not primarily responsible for breaking seed dormancy.

3. **Evaluate the Second Option - Gibberellic Acid**:
- Gibberellic acid (GA) is a well-known plant hormone that promotes seed germination by breaking dormancy.
- It stimulates the production of enzymes that help in the mobilization of food reserves in the seed, making it a key hormone in breaking dormancy.

4. **Evaluate the Third Option - Ethylene**:
- Ethylene is another plant hormone that plays a significant role in various plant processes, including the breaking of seed dormancy.
- It helps in the germination process by promoting the growth of the seed and the emergence of the seedling.

5. **Evaluate the Last Option - All of the Above**:
- Since Cytokinins, Gibberellic Acid, and Ethylene all contribute to breaking seed dormancy in different ways, the option "All of the above" is indeed correct.

### Conclusion:
The correct answer is **All of the above** (Cytokinins, Gibberellic Acid, and Ethylene) as they all play a role in breaking the dormancy of seeds.

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