Which one is a Water Fern

Options

A. Azolla
B. Salvinia
C. Marsilea
D. All the above.

Answer

**Step-by-Step Solution:**

1. **Understanding the Term "Water Fern":**
- Water ferns are a type of fern that typically grow in aquatic environments. They belong to the group of plants known as pteridophytes.

2. **Identifying the Options:**
- The options given are:
- Option 1: Azolla
- Option 2: Salvinia
- Option 3: Marsilia
- Option 4: All of the above

3. **Analyzing Each Option:**
- **Azolla:** This is a small floating fern often found in freshwater environments. It is known for its symbiotic relationship with nitrogen-fixing cyanobacteria.
- **Salvinia:** This is another floating aquatic fern that can be found in ponds and slow-moving waters. It has unique leaves that help it float.
- **Marsilia:** This is a water fern that resembles a four-leaf clover and is typically found in shallow water bodies.

4. **Conclusion:**
- Since all three options (Azolla, Salvinia, and Marsilia) are recognized as water ferns, the correct answer to the question is:
- **Option 4: All of the above.**