Select the incorrect statement w.r.t. dinoflagellates

Options

A. May appear yellow, green, brown, blue or red in colour
B. Some member releases toxin that may even kill other marine animals
C. Have two flagella, both lie transversely
D. They are mostly marine organism.

Answer

To solve the question, we need to identify the incorrect statement regarding dinoflagellates from the provided options. Let's analyze each option step by step.

### Step 1: Analyze the first statement
**Statement:** Dinoflagellates may appear yellow, green, blue, or red in color.
**Analysis:** This statement is correct. Dinoflagellates can exhibit various colors due to the presence of different pigments like chlorophyll A, chlorophyll B, and other accessory pigments.

### Step 2: Analyze the second statement
**Statement:** Some members release toxins that may even kill other marine animals.
**Analysis:** This statement is also correct. Certain dinoflagellates are known to produce toxins that can be harmful to marine life, leading to phenomena such as "red tides."

### Step 3: Analyze the third statement
**Statement:** They have two flagella both lie transversely.
**Analysis:** This statement is incorrect. Dinoflagellates possess two flagella, but one flagellum lies longitudinally while the other lies transversely. Therefore, stating that both lie transversely is incorrect.

### Step 4: Analyze the fourth statement
**Statement:** They are mostly marine organisms.
**Analysis:** This statement is correct. Most dinoflagellates are indeed marine organisms, thriving in oceanic environments.

### Conclusion
After analyzing all the statements, we conclude that the incorrect statement is: **"They have two flagella both lie transversely."**

### Final Answer
The incorrect statement regarding dinoflagellates is: **"They have two flagella both lie transversely."**

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