Green algae are considered ……………… of all terrestrial plants .

Answer

**Step-by-Step Solution:**

1. **Understanding Green Algae**: Green algae are a group of photosynthetic organisms that are primarily found in aquatic environments. They contain chlorophyll, which allows them to perform photosynthesis.

2. **Historical Context**: Green algae are believed to have appeared on Earth approximately 800 million years ago. This long evolutionary history is significant in understanding their relationship with terrestrial plants.

3. **Evolutionary Significance**: Green algae are considered to be the ancestors of all terrestrial plants. This is because they share common characteristics, such as the presence of chlorophyll A and B, which are essential for photosynthesis.

4. **Transition to Terrestrial Life**: Over time, green algae evolved into more complex forms, leading to the development of vascular plants. Vascular plants have specialized tissues (xylem and phloem) that transport water and nutrients throughout the plant, which is crucial for life on land.

5. **Conclusion**: Therefore, green algae are considered the ancestors of all terrestrial plants due to their evolutionary lineage and the role they played in the transition from aquatic to terrestrial environments.

**Final Answer**: Green algae are considered the ancestors of all terrestrial plants.

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