Embryo is not formed in thallophyta due to :-

Options

A. Zygotic meiosis
B. Zygotic mitosis
C. Sporangial meiosis
D. Gametic meiosis.

Answer

### Step-by-Step Solution:

1. **Understanding Thallophyta**:
- Thallophyta is a division that includes organisms like algae, fungi, and lichens. These organisms do not have a differentiated body structure (i.e., they lack distinct stems, leaves, and roots).

2. **Characteristics of Thallophyta**:
- Thallophytes are primarily freshwater organisms and do not possess vascular tissues such as phloem and xylem, which are essential for the transport of nutrients and water in higher plants.

3. **Life Cycle of Thallophyta**:
- Most thallophytes exhibit a haplontic life cycle. In this cycle, the dominant phase is the gametophyte, which is haploid (n).

4. **Gametophyte and Gamete Formation**:
- The gametophyte produces gametes (sperm and egg) through mitosis, as it remains in the haploid state (n).

5. **Fertilization and Zygote Formation**:
- When the male and female gametes fuse during fertilization, they form a zygote, which is diploid (2n).

6. **Zygotic Meiosis**:
- In thallophytes, the zygote does not develop into an embryo. Instead, it undergoes zygotic meiosis immediately after formation. This means the zygote divides meiotically to produce four haploid spores (n), rather than developing into an embryo.

7. **Conclusion**:
- Since the zygote undergoes meiosis instead of developing into an embryo, thallophytes do not form embryos. Therefore, the correct answer to the question is that the embryo is not formed in thallophyta due to **zygotic meiosis**.