Algae with r ich source of protein is _________ .

Explanation

**Step-by-Step Solution:**

1. **Understanding Algae**: Algae are simple, typically aquatic organisms that can perform photosynthesis. They are classified into different groups based on their pigmentation and structure.

2. **Identifying Protein-Rich Algae**: Among various types of algae, some are known for their high protein content. It is important to identify which specific type is recognized for being particularly rich in protein.

3. **Recognizing Spirulina**: Spirulina is a type of blue-green algae (cyanobacteria) that is well-known for its high protein content. It is often marketed as a dietary supplement due to its nutritional benefits.

...