Mycorrhiza works as

Options

A. modified shoot
B. a root hair in adverse condition
C. an organism for propagation
D. mechanical tissus for support

Answer

### Step-by-Step Solution:

1. **Understanding Mycorrhiza**: Mycorrhiza refers to the symbiotic association between fungi and plant roots. This relationship is beneficial for both organisms.

2. **Function of Mycorrhiza**: The fungi in mycorrhizae extend the root system of plants, which enhances the plant's ability to absorb water and nutrients from the soil.

3. **Benefits to Plants**: In return for the nutrients and water they provide, the fungi receive carbohydrates and growth factors from the plants. This mutual exchange is crucial for the survival and growth of both organisms.

4. **Role in Adverse Conditions**: Mycorrhizae can help plants tolerate adverse conditions, such as drought or nutrient deficiency. In particular, ectomycorrhizae can function similarly to root hairs, especially in plants like Pinus (pines), which do not have root hairs.

5. **Evaluating Options**: The question provides four options:
- A. Modified shoot
- B. A root hair in adverse condition
- C. An organism for propagation
- D. Mechanical tissue for support

6. **Identifying the Correct Answer**: Given that mycorrhizae act as extensions of the root system and can function like root hairs in certain conditions, the correct answer is **B. A root hair in adverse condition**.

### Final Answer:
**B. A root hair in adverse condition**

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