Sporophyte is completely dependent in

Options

A. Selaginella
B. Dryopteris
C. Riccia
D. Pinus.

Answer

**Step-by-Step Solution:**

1. **Understanding Sporophyte and Gametophyte:**
- The sporophyte is a stage in the life cycle of plants that produces spores. In contrast, the gametophyte is the stage that produces gametes (sperm and eggs).

2. **Identifying the Plant Group:**
- The question asks where the sporophyte is completely dependent. In the plant kingdom, bryophytes (like mosses and liverworts) are known for having a dominant gametophyte stage and a dependent sporophyte stage.

3. **Examining the Options:**
- The options provided are:
a. Platynella (pteridophyte)
b. Dryopteris (pteridophyte)
c. Rhyssia (bryophyte)
d. Pinus (gymnosperm)

4. **Analyzing Each Option:**
- **Platynella:** This belongs to the pteridophytes, where the sporophyte is independent. Thus, it is incorrect.
- **Dryopteris:** This is also a pteridophyte, where the sporophyte is independent. Thus, it is incorrect.
- **Rhyssia:** This is a bryophyte, where the sporophyte is completely dependent on the gametophyte for nutrition. Thus, it is correct.
- **Pinus:** This is a gymnosperm, where the sporophyte is independent. Thus, it is incorrect.

5. **Conclusion:**
- The correct answer is **Rhyssia**, as the sporophyte in bryophytes is completely dependent on the gametophyte.

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