Most conspicuous alteration of generation occurs in :-

Options

A. Thallophyta
B. Bryophyta
C. Pteridophyta
D. Spermatophyta

Answer

To solve the question regarding which group of plants exhibits the most conspicuous alternation of generations, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Concept of Alternation of Generations**:
- Alternation of generations refers to the life cycle of plants where there are two distinct phases: the diploid sporophyte phase and the haploid gametophyte phase.

2. **Identify the Groups of Plants**:
- The options provided are Thalophyta, Bryophyta, Pteridophyta, and Spermatophyta. Each of these groups has a different relationship between their sporophyte and gametophyte generations.

3. **Analyze Each Group**:
- **Thalophyta**: This group includes algae, which primarily reproduce asexually and do not have a conspicuous alternation of generations.
- **Bryophyta**: In mosses, the gametophyte is the dominant phase, while the sporophyte is dependent on the gametophyte and not very conspicuous.
- **Pteridophyta**: This group includes ferns. In ferns, both the sporophyte and gametophyte are independent and free-living. The sporophyte is larger and more conspicuous than the gametophyte.
- **Spermatophyta**: This group includes seed plants, where the sporophyte is dominant, and the gametophyte is reduced and dependent on the sporophyte.

4. **Determine the Most Conspicuous Group**:
- Among these groups, Pteridophyta (ferns) exhibits the most conspicuous alternation of generations because both the sporophyte and gametophyte are independent, but the sporophyte is significantly larger and more noticeable.

5. **Conclusion**:
- Therefore, the correct answer to the question is **Pteridophyta**.

### Final Answer:
Most conspicuous alternation of generation occurs in **Pteridophyta**.