Read the statement and choose the correct option
I. Secretion of interferons is a physiological barrier of innate immunity
II. T-lymphocytes are responsible for cell mediated immunity
III. Injection given against snake venom is a type of active immunisation
IV. Antibodies produced during allergic reactions are of IgA type
(a) i and ii are correct
(b) ii and iv alone are correct
(c) iii alone is correct
(d) ii alone is correct

Options

A. i and ii are correct
B. ii and iv alone are correct
C. iii along is correct
D. ii alone is correct

Answer

To solve the question, we need to evaluate each of the four statements regarding immunity and identify which ones are correct.

### Step-by-Step Solution:

1. **Evaluate Statement I:**
- **Statement:** Secretion of interferons is a physiological barrier of innate immunity.
- **Analysis:** Interferons are proteins produced by virus-infected cells that help inhibit viral replication and activate immune cells. They are not classified as a physiological barrier; rather, they are considered a chemical barrier of innate immunity.
- **Conclusion:** This statement is **incorrect**.

2. **Evaluate Statement II:**
- **Statement:** T-lymphocytes are responsible for cell-mediated immunity.
- **Analysis:** T-lymphocytes (T-cells) play a crucial role in cell-mediated immunity by recognizing and responding to infected or cancerous cells. They are essential for the immune response.
- **Conclusion:** This statement is **correct**.

3. **Evaluate Statement III:**
- **Statement:** Injection given against snake venom is a type of active immunization.
- **Analysis:** An injection against snake venom (antivenom) is an example of passive immunization, where pre-formed antibodies are introduced into the body. Active immunization involves the introduction of antigens to stimulate the body to produce its own antibodies.
- **Conclusion:** This statement is **incorrect**.

4. **Evaluate Statement IV:**
- **Statement:** Antibodies produced during allergic reactions are of IgA type.
- **Analysis:** The antibodies involved in allergic reactions are primarily of the IgE type, not IgA. IgA is mainly found in mucosal areas and secretions.
- **Conclusion:** This statement is **incorrect**.

### Summary of Findings:
- Statement I: Incorrect
- Statement II: Correct
- Statement III: Incorrect
- Statement IV: Incorrect

### Final Conclusion:
The only correct statement is Statement II. Therefore, the correct option is **(d) ii alone is correct**.

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