Hypnotoxin is a poisonous fluid produced by

Options

A. Parasitic protozoa
B. Nematocysts
C. Sponges
D. Ascaris

Answer

### Step-by-Step Solution:

1. **Understanding the Question**: The question asks about "Hypnotoxin," which is described as a poisonous fluid. We need to identify which organism produces this fluid from the given options.

2. **Analyzing the Options**:
- **Option 1: Parasitic Protozoa**: While some protozoa can be harmful, they are not known for producing hypnotoxin.
- **Option 2: Nematocyst**: Nematocysts are specialized cells found in cnidarians (like hydra) that contain stinging structures and toxins.
- **Option 3: Sponges**: Sponges do not produce hypnotoxin; they have a different type of defense mechanism.
- **Option 4: Ascites**: Ascites refers to a condition, not an organism, and is unrelated to the production of hypnotoxin.

3. **Identifying the Correct Answer**: From the analysis, it is clear that the correct answer is **Option 2: Nematocyst**. Nematocysts are specialized cells in cnidarians that produce various types of toxins, including hypnotoxin.

4. **Understanding Nematocysts**: Nematocysts, also known as cnidoblasts or nematoblasts, are stinging cells that contain a coiled thread and a poisonous fluid. When triggered, they can inject this toxin into prey or predators.

5. **Functions of Nematocysts**:
- They serve three main functions:
- **Penetrance**: To paralyze and kill prey.
- **Glutinance**: For attachment and defense.
- **Volvins**: To coil around and capture prey.

6. **Conclusion**: The hypnotoxin is produced by the nematocysts found in cnidarians like hydra, making **Option 2** the correct answer.