Mycorrhiza is a

Options

A. Symbiotic association of fungi with algae
B. Symbiotic association of fungi with angiosperms
C. Symbiotic association of fungi with gymnosperms
D. Symbiotic association of fungi with the roots of certain seed-bearing plants

Answer

### Step-by-Step Solution:

1. **Understanding Mycorrhiza**: Mycorrhiza refers to a symbiotic association between fungi and plant roots. It is crucial to recognize that mycorrhiza is specifically a relationship involving fungi.

2. **Identifying the Options**: The question provides four options regarding the nature of mycorrhiza:
- A) Symbiotic association of fungi with algae
- B) Symbiotic association of fungi with angiosperms
- C) Symbiotic association of fungi with gymnosperms
- D) Symbiotic association of fungi with the roots of certain seed-bearing plants

3. **Analyzing the Correct Option**:
- While mycorrhiza can have associations with various types of plants, the most accurate description is that it specifically involves fungi forming a symbiotic relationship with the roots of seed-bearing plants, which includes both angiosperms and gymnosperms.
- Therefore, option D is the most comprehensive and correct choice, as it encompasses the relationship with both angiosperms and gymnosperms.

4. **Conclusion**: The correct answer to the question "Mycorrhiza is a" is option D: "symbiotic association of fungi with the roots of certain seed-bearing plants."