Hypersensivity to an allergen is due to

Options

A. aberrant functioning of the immune mechanism
B. increase in ambient temperature
C. age of the individual
D. food habits

Explanation

**Step-by-Step Solution:**

1. **Understanding Hypersensitivity**: Hypersensitivity refers to an exaggerated or inappropriate immune response to a substance that is typically harmless, known as an allergen. This can lead to various allergic reactions.

2. **Identifying the Allergen**: An allergen is a foreign substance that triggers an immune response. Common allergens include pollen, dust mites, certain foods, and insect venom.

3. **Mechanism of Hypersensitivity**: In hypersensitivity reactions, the immune system reacts excessively to the allergen. This can lead to harmful effects on the body, such as inflammation, tissue damage, and other allergic symptoms.

4. **Types of Hypersensitivity**: There are different types of hypersensitivity reactions (Type I, II, III, and IV), but Type I hypersensitivity (immediate hypersensitivity) is the most common and is often associated with allergens like pollen and food.

5. **Cause of Hypersensitivity**: The question asks for the cause of hypersensitivity to an allergen. The correct answer is that it is due to the aberrant functioning of the immune mechanism. This means that the immune system is not functioning properly, leading to an exaggerated response to the allergen.

6. **Conclusion**: Therefore, the correct option is that hypersensitivity to an allergen is due to the aberrant functioning of the immune mechanism.

**Final Answer**: Hypersensitivity to an allergen is due to aberrant functioning of the immune mechanism.

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