Positively photoblastic seeds germinate only in presence of

Options

A. soil
B. air
C. light
D. all of these

Answer

To solve the question about positively photoblastic seeds, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Definition of Photoblastic Seeds**:
- Photoblastic seeds are seeds that require light for germination. They are sensitive to light conditions.

2. **Identify the Types of Photoblastic Seeds**:
- There are two types: positively photoblastic seeds, which germinate in the presence of light, and negatively photoblastic seeds, which germinate in darkness.

3. **Focus on Positively Photoblastic Seeds**:
- Positively photoblastic seeds specifically need light to initiate the germination process.

4. **Consider the Options Given**:
- The options provided are:
1. Soil
2. Air
3. Light
4. All of these

5. **Analyze Each Option**:
- **Soil**: While soil provides nutrients and a medium for growth, it is not a requirement for germination in terms of light sensitivity.
- **Air**: Air is necessary for respiration, but it does not directly influence the light requirement for germination.
- **Light**: This is the critical factor for positively photoblastic seeds, as they require light to germinate.
- **All of these**: This option suggests that all factors are equally necessary, which is not accurate for positively photoblastic seeds.

6. **Conclusion**:
- The correct answer is option 3: **Light**. Positively photoblastic seeds germinate only in the presence of light.

### Final Answer:
Positively photoblastic seeds germinate only in the presence of **light**.

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