Which of the following is a non-specific type of defense that is present at the time of birth?

Options

A. Acquired Immunity
B. Humoral immune response
C. Cell mediated immunity
D. Innate immunity

Explanation

**Step-by-Step Solution:**

1. **Understanding the Question:**
The question asks for a type of defense that is non-specific and present at birth. This means we are looking for an innate form of immunity that does not require prior exposure to pathogens.

2. **Analyzing the Options:**
- **Acquired Immunity:** This type of immunity develops over time through exposure to pathogens or through vaccination. It is specific and not present at birth.
- **Humoral Immune Response:** This involves antibodies and is part of the acquired immunity. It is also not present at birth.
- **Cell Mediated Immunity:** This involves the activation of immune cells rather than antibodies. Like humoral immunity, it is part of acquired immunity and not present at birth.
- **Innate Immunity:** This is the type of immunity that is present at birth. It includes physical barriers (like skin) and physiological barriers (like mucous membranes) and is non-specific.

3. **Identifying the Correct Answer:**
Since innate immunity is the only option that is non-specific and present at the time of birth, it is the correct answer.

4. **Conclusion:**
The answer to the question is **innate immunity**.

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