The spread of living pteridophytes is limited and is restricted to narrow geographical region because

Options

A. Requirement of water by sporophyte for syngamy
B. Cool, damp, shady places requiredment to gametophytes
C. Water independent fertilization
D. The development of vascular tissues in plant body.

Answer

To answer the question regarding why the spread of living pteridophytes is limited and restricted to narrow geographical regions, we can break down the explanation into several key points:

### Step-by-Step Solution:

1. **Understanding Pteridophytes**:
- Pteridophytes are vascular plants that reproduce via spores and have a life cycle that includes both a sporophyte (diploid) and a gametophyte (haploid) stage.

2. **Water Requirement for Fertilization**:
- The sporophyte stage of pteridophytes requires water for syngamy (fertilization) to occur. This means that the sperm must swim through water to reach the egg.

3. **Gametophyte Habitat**:
- The gametophyte stage of pteridophytes thrives in cool, damp, and shady environments. These conditions are essential for their growth and development.

4. **Geographical Limitations**:
- Due to the specific habitat requirements of the gametophyte (cool, damp, shady places) and the need for water during fertilization, pteridophytes are often restricted to narrow geographical regions where such conditions are met.

5. **Misconception about Water Independence**:
- It is important to note that pteridophytes do not have water-independent fertilization. This is a key factor that limits their spread, as they cannot thrive in arid or dry environments.

6. **Development of Vascular Tissues**:
- While pteridophytes do have vascular tissues, which allow them to transport water and nutrients, the requirement for specific environmental conditions still limits their distribution.

### Conclusion:
The spread of living pteridophytes is limited to narrow geographical regions primarily due to their dependence on water for fertilization and the specific habitat requirements of their gametophyte stage.