The type of immunity that is present at the time of birth in human is:

Options

A. None of these
B. Both of these
C. Acquired immunity
D. Innate immunity

Answer

**Step-by-Step Solution:**

1. **Understanding Immunity Types**:
- Immunity can be classified into two main types: acquired (adaptive) immunity and innate (natural) immunity.

2. **Defining Acquired Immunity**:
- Acquired immunity is specific to pathogens and develops over time. It involves the production of antibodies by B-cells after exposure to a pathogen. This type of immunity is not present at birth and develops as the individual encounters various pathogens.

3. **Defining Innate Immunity**:
- Innate immunity is the type of immunity that is present at birth. It is a non-specific defense mechanism that includes physical barriers (like skin), physiological barriers (like stomach acid and saliva), and cellular barriers (like white blood cells).

4. **Identifying the Correct Answer**:
- Since the question asks for the type of immunity present at the time of birth, the correct answer is innate immunity.

5. **Conclusion**:
- Therefore, the type of immunity that is present at the time of birth in humans is innate immunity.

**Final Answer**: Innate immunity.

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