A dinoflagellate with nematocysts is

Options

A. Nematodinium
B. Ceratium
C. Gonyaulax
D. Symbodinium.

Answer

To solve the question "A dinoflagellate with nematocysts is", we need to identify which dinoflagellate genus contains nematocysts. Here's a step-by-step breakdown of the solution:

### Step 1: Understand Dinoflagellates
Dinoflagellates are unicellular eukaryotic organisms that belong to the kingdom Protista. They are characterized by their unique flagella and can be found in various aquatic environments.

**Hint:** Remember that dinoflagellates are unicellular and belong to the Protista kingdom.

### Step 2: Identify Nematocysts
Nematocysts are specialized subcellular structures that can be found in certain organisms, including some dinoflagellates. They are typically associated with the phylum Cnidaria, where they serve a defensive or predatory function.

**Hint:** Nematocysts are not exclusive to dinoflagellates; they are also found in Cnidarians.

### Step 3: Determine the Specific Genus
The question asks for a specific dinoflagellate that contains nematocysts. The genus known to contain nematocysts in dinoflagellates is **Nematodinium**. This genus has a unique type of nematocyst that differs from those found in Cnidarians.

**Hint:** Look for the genus that specifically mentions the presence of nematocysts.

### Step 4: Evaluate Other Options
The other options provided (Serratium, Gonyaulax, and Cymbodoce) do not contain nematocysts:
- **Serratium** is a genus of dinoflagellates but does not have nematocysts.
- **Gonyaulax** is known for causing red tides but also lacks nematocysts.
- **Cymbodoce** is an endosymbiotic dinoflagellate that has mucocysts instead of nematocysts.

**Hint:** Compare each option against the characteristic of having nematocysts.

### Conclusion
After evaluating the options, the correct answer to the question "A dinoflagellate with nematocysts is" is **Nematodinium**.

**Final Answer:** Nematodinium