Plants of thallophyta are :-

Options

A. Haploid and gametophyte
B. Haploid and sporophyte
C. Diploid and gametophyte
D. Diploid and sporophyte

Answer

To answer the question "Plants of Thallophyta are:", we will analyze the options provided and determine the correct characteristics of Thallophyta.

### Step-by-Step Solution:

1. **Understanding Thallophyta**:
- Thallophyta is a group of simple plants that includes algae, fungi, and some other similar organisms. They are characterized by their simple structure and lack of true roots, stems, and leaves.

2. **Identifying Key Characteristics**:
- Thallophytes are primarily haploid organisms. This means they have only one set of chromosomes (n).
- They reproduce through spores, which are also haploid.

3. **Examining the Options**:
- **Option A: Haploid and Gametophyte**: This option suggests that Thallophyta are haploid and represent the gametophyte stage. This is correct because the dominant phase in many thallophytes is indeed the gametophyte, which is haploid.
- **Option B: Haploid and Sporophyte**: This option is incorrect because the sporophyte is typically diploid (2n) and not the dominant phase in Thallophyta.
- **Option C: Diploid and Gametophyte**: This option is incorrect because gametophytes are haploid, not diploid.
- **Option D: Diploid and Sporophyte**: This option is also incorrect as sporophytes are diploid but not the primary form in Thallophyta.

4. **Conclusion**:
- After analyzing all the options, the correct answer is **Option A: Haploid and Gametophyte**. Thallophyta primarily exist in the gametophyte stage, which is haploid.

### Final Answer:
Plants of Thallophyta are **Haploid and Gametophyte**.