Which phase in pteridophytes is diploid in nature?

Explanation

### Step-by-Step Solution:

1. **Understanding Pteridophytes**:
- Pteridophytes are primitive vascular plants that possess xylem and phloem. They are autotrophic, meaning they can produce their own food through photosynthesis. Examples include ferns and horsetails.

2. **Life Cycle of Pteridophytes**:
- The life cycle of pteridophytes involves two main phases: the sporophyte phase and the gametophyte phase.

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