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

To answer the question, "Which of the following is a non-specific type of defense that is present at the time of birth?", we will analyze the options provided and identify the correct one step by step.

### Step-by-Step Solution:

1. **Understanding the Types of Immunity**:
- Immunity can be classified into two main types: **innate (non-specific) immunity** and **adaptive (specific) immunity**.
- Innate immunity is the body's first line of defense and is present from birth. It acts against a wide range of pathogens in a non-specific manner.

2. **Identifying Innate Immunity**:
- Innate immunity includes physical barriers (like skin), chemical barriers (like stomach acid), and immune cells (like macrophages) that respond to any foreign invader without prior exposure.
- Since it is present at birth and does not target specific pathogens, it is considered non-specific.

3. **Evaluating Other Options**:
- **Adaptive Immunity**: This type of immunity develops over time and is specific to particular pathogens. It includes:
- **Humoral Immunity**: Mediated by B lymphocytes and involves the production of antibodies against specific antigens.
- **Cell-Mediated Immunity**: Mediated by T lymphocytes and also targets specific pathogens.
- Both humoral and cell-mediated immunity are not present at birth and are pathogen-specific.

4. **Conclusion**:
- The only option that fits the criteria of being non-specific and present at the time of birth is **innate immunity**.

Thus, the correct answer is **innate immunity**.

### Final Answer:
The non-specific type of defense that is present at the time of birth is **innate immunity**.

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