Sieve cells occur in

Options

A. Angiosperms only
B. Gymnosperms only
C. Pteridophytes only
D. Pteridophytes and gymnosperms

Answer

**Step-by-Step Solution:**

1. **Understanding Sieve Cells**: Sieve cells are specialized cells that are part of the phloem tissue in plants. They are involved in the transport of nutrients, particularly sugars, throughout the plant.

2. **Identifying Plant Groups**: Sieve cells are primarily found in certain groups of plants. The main groups to consider are:
- Angiosperms (flowering plants)
- Gymnosperms (non-flowering seed plants)
- Pteridophytes (ferns and their relatives)

3. **Sieve Cells in Different Plant Groups**:
- In **Angiosperms**, the phloem consists of sieve tube elements and companion cells.
- In **Gymnosperms**, sieve cells are present but they are not as specialized as those in angiosperms.
- In **Pteridophytes**, sieve cells are also present but are less common.

4. **Conclusion**: Based on the information, sieve cells are found in both gymnosperms and pteridophytes, but they are more prominent in gymnosperms. Therefore, the correct answer to the question "Sieve cells occur in" is:
- **Pteridophytes and Gymnosperms**.

**Final Answer**: Sieve cells occur in Pteridophytes and Gymnosperms.

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