In bryophytes

Options

A. sporophytes are dependent upon gametophytes
B. sporophyte and gametophyte generation are independent
C. sporophyte in itself completes the life cycle
D. gametophytes are dependent upon sporophytes.

Explanation

### Step-by-Step Solution:

1. **Understanding Bryophytes**:
- Bryophytes are non-vascular plants that include mosses, liverworts, and hornworts. They have a unique life cycle that involves two distinct phases: the gametophyte and the sporophyte.

2. **Identifying the Phases**:
- **Gametophyte Phase**: This is the haploid phase (n) where the plant produces gametes (sperm and eggs). In bryophytes, the gametophyte is the dominant and long-lived phase of the life cycle.
- **Sporophyte Phase**: This is the diploid phase (2n) that develops from the fertilization of gametes. The sporophyte is typically shorter-lived and is dependent on the gametophyte for nutrition.

3. **Dependency Relationship**:
- The sporophyte remains attached to the gametophyte for a significant part of its life. It relies on the gametophyte for its nutritional needs, indicating a clear dependency.

4. **Evaluating the Options**:
- **Option 1**: "Sporophytes are dependent upon gametophytes." - This is correct as the sporophyte derives its nutrition from the gametophyte.
- **Option 2**: "Sporophytes and gametophyte generations are independent." - This is incorrect because the sporophyte is dependent on the gametophyte.
- **Option 3**: "Sporophyte in itself completes the life cycle." - This is also incorrect as both phases are necessary for the life cycle.
- **Option 4**: "Gametophytes are dependent on sporophytes." - This is incorrect since gametophytes are not dependent on sporophytes.

5. **Conclusion**:
- The correct answer is **Option 1**: "Sporophytes are dependent upon gametophytes."