The largest alga is

Options

A. Laminaria
B. Macrocystis
C. Nereocystis
D. Sargassum.

Answer

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks for the largest alga among the given options: Laminaria, Microcystis, Neurocystis, and Sargassum.

2. **Identifying the Types of Algae**:
- Laminaria: This is a type of brown algae, commonly known as kelp. It is large but not the largest.
- Microcystis: This is a genus of freshwater cyanobacteria, not typically classified as a large alga.
- Neurocystis: This is another type of brown algae but is smaller in size compared to others.
- Sargassum: This is also a type of brown seaweed but is free-floating and not the largest.

3. **Determining the Largest Alga**:
- Among the options, Microcystis can be eliminated as it is not a true alga in the context of size.
- Laminaria and Sargassum are large but not the largest.
- Neurocystis is also not the largest.
- The largest alga is actually Macrocystis, which can grow up to 30 to 56 meters in length.

4. **Conclusion**: The correct answer is Microcystis, as it is the largest alga among the options provided.

**Final Answer**: The largest alga is **Macrocystis**.

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