The cyanobacteria are also referred to as:-

Options

A. Golden algae
B. Slime moulds
C. Blue green algae
D. Protists

Answer

### Step-by-Step Solution:

1. **Identify the Organism**: The question asks about cyanobacteria. Begin by understanding what cyanobacteria are.

2. **Classification**: Recognize that cyanobacteria belong to the kingdom Monera. This kingdom consists of prokaryotic organisms, which means they lack a true nucleus and membrane-bound organelles.

3. **Characteristics of Cyanobacteria**: Understand that cyanobacteria are photosynthetic organisms. They can produce their own food through photosynthesis, which is a key characteristic of algae.

4. **Coloration**: Note that cyanobacteria have a blue-green pigment, which is why they are often referred to as blue-green algae.

5. **Evaluate Options**: Now, look at the provided options:
- Golden alga: This is incorrect as golden algae belong to the kingdom Protista and are eukaryotic.
- Slime molds: This is also incorrect because slime molds are part of the kingdom Protista and are not prokaryotic.
- Blue-green alga: This is the correct option since cyanobacteria are indeed referred to as blue-green algae due to their color and photosynthetic ability.
- Protista: This option is incorrect as cyanobacteria do not belong to this kingdom; they are prokaryotes.

6. **Conclusion**: Based on the analysis, the correct answer is that cyanobacteria are also referred to as blue-green algae.

### Final Answer:
Cyanobacteria are also referred to as **blue-green algae**.

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