Thallus of Riccia is

Options

A. Haploid
B. Diploid
C. Triploid
D. Tetraploid.

Answer

**Step-by-Step Solution:**

1. **Understanding the Organism**: Riccia is a genus of liverworts, which are non-vascular plants belonging to the group of bryophytes.

2. **Identifying the Thallus**: The thallus of Riccia refers to its plant body, which is flat and green. It is important to note that the thallus is not differentiated into roots, stems, or leaves like higher plants.

3. **Determining the Nature of the Thallus**: The thallus of Riccia is gametophytic in nature. In the plant life cycle, gametophytes are the haploid stage that produces gametes.

4. **Understanding Ploidy Levels**:
- Haploid (n): One set of chromosomes.
- Diploid (2n): Two sets of chromosomes.
- Triploid (3n): Three sets of chromosomes.
- Tetraploid (4n): Four sets of chromosomes.

5. **Conclusion**: Since the thallus of Riccia is gametophytic, it is haploid. Therefore, the correct answer is that the thallus of Riccia is haploid.

**Final Answer**: The thallus of Riccia is haploid (Option 1).

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