Which of the following toxic substances is responsible is responsible for the high malarial fever?

Options

A. Haemoglobin
B. haemocyanin
C. Haemozoin
D. haemoriden

Answer

### Step-by-Step Solution:

1. **Understanding the Question**: The question asks which toxic substance is responsible for high malarial fever. Malarial fever is caused by the Plasmodium parasite, which infects red blood cells.

2. **Analyzing the Options**:
- **Option A: Hemoglobin**: This is a respiratory pigment found in red blood cells. It is not toxic and is a normal component of the body. Therefore, this option is incorrect.
- **Option B: Hemocyanin**: This is another respiratory pigment found in some invertebrates, such as mollusks and arthropods. It is not toxic and is not related to malaria. Thus, this option is also incorrect.
- **Option C: Hemozoin**: This is a biocrystal synthesized by the Plasmodium parasite during the digestion of hemoglobin. It is indeed a toxic substance that contributes to the symptoms of malaria, including high fever. This option is likely the correct answer.
- **Option D: Hemorrhidin**: This substance does not exist in scientific literature and seems to be a fictional or erroneous term. Therefore, this option is incorrect.

3. **Conclusion**: After analyzing all the options, the only toxic substance responsible for high malarial fever is **Hemozoin** (Option C).

### Final Answer:
The toxic substance responsible for high malarial fever is **Hemozoin**.

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