The root-fungus association is :

Options

A. Coleorhiza
B. Rhizomorphs
C. Mycorrhiza
D. None of these

Answer

To answer the question "The root-fungus association is:", we need to analyze the given options one by one and identify the correct association.

### Step-by-Step Solution:

1. **Understand the Question**: We are asked to identify the type of association that occurs between roots and fungi. This is a common biological interaction that can be beneficial for both organisms involved.

2. **Analyze the Options**:
- **Option 1: Choleryza**: This is described as a sheath-like structure found in monocot seeds that covers the radical (the embryonic root). It does not represent a root-fungus association, so this option is incorrect.

- **Option 2: Rhizomorphs**: These are root-like structures formed by certain fungi, consisting of a network of hyphae. While they are related to fungi, they do not specifically denote an association with plant roots. Therefore, this option is also incorrect.

- **Option 3: Mycorrhiza**: This term refers to the symbiotic association between the roots of higher plants and fungi. In this relationship, the plant provides carbohydrates (sugars) produced through photosynthesis to the fungus, while the fungus aids the plant in absorbing nutrients and water, particularly phosphorus. This is a well-known and beneficial interaction, making this option the correct answer.

3. **Conclusion**: Based on the analysis of the options, the correct answer is **Mycorrhiza**.

### Final Answer:
The root-fungus association is **Mycorrhiza**.

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