Which of the following is the unique feature of brophytes ?

Options

A. Presence of vascular bundles
B. Reproduction only by the formation of gametes
C. Gametophyte attached to the sporophyte
D. Sporophyte attached to the gametophyte

Answer

To solve the question regarding the unique feature of bryophytes, we will analyze each option provided and determine which one correctly describes a characteristic exclusive to bryophytes.

### Step-by-Step Solution:

1. **Understanding Bryophytes**:
- Bryophytes are non-vascular plants that include mosses, liverworts, and hornworts. They are known for their ability to thrive in both terrestrial and aquatic environments.

2. **Analyzing the Options**:
- **Option A: Presence of vascular bundles**:
- Bryophytes do not have vascular tissues (xylem and phloem), which are present in higher plants. Therefore, this option is incorrect.

- **Option B: Reproduction only by the formation of gametes**:
- While bryophytes reproduce sexually through gametes, they also have asexual reproduction methods. Thus, this option is not unique to bryophytes.

- **Option C: Gametophyte attached to the sporophyte**:
- In bryophytes, the sporophyte is dependent on the gametophyte for nutrition and is attached to it. However, this statement is misleading as it suggests a different relationship than what actually occurs.

- **Option D: Sporophyte attached to the gametophyte**:
- This is the correct statement. In bryophytes, the sporophyte (diploid stage) is indeed attached to and dependent on the gametophyte (haploid stage) for nourishment.

3. **Conclusion**:
- The unique feature of bryophytes is that the sporophyte is attached to the gametophyte. Therefore, the correct answer is **Option D**.

### Final Answer:
**D: Sporophyte attached to the gametophyte.**