Differentiate between Sieve cells and sieve tubes

Explanation

**Step-by-Step Solution:**

1. **Definition of Sieve Cells and Sieve Tubes:**
- Sieve cells are elongated cells found in the phloem of gymnosperms and some other plants, responsible for the transport of nutrients.
- Sieve tubes are specialized structures in the phloem of angiosperms (flowering plants) that facilitate the transport of sugars and other organic compounds.

2. **Presence of Companion Cells:**
- Sieve cells do not have companion cells associated with them.
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