Innate immunity is non specific defence present from the time of birth. It consists of -

Options

A. skin, mucus coating of the epthelium , interferons, cytokines
B. neutrophilis, monocytes, macrophages, natural killer cells
C. both a and b
D. None of these

Answer

### Step-by-Step Solution:

1. **Definition of Innate Immunity**: Innate immunity is the first line of defense against pathogens and is present from birth. It is a non-specific form of immunity that does not adapt or change in response to specific pathogens.

2. **Components of Innate Immunity**: Innate immunity comprises physical barriers and cellular components that work together to prevent infection.

3. **Physical Barriers**:
- **Skin**: The skin acts as a physical barrier that prevents the entry of pathogens.
- **Mucous Coating**: Mucous membranes line various body cavities and secrete mucus, which traps pathogens and prevents their entry.
- **Interferons and Cytokines**: These are signaling proteins that are part of the immune response but are not physical barriers. They help in communication between cells during immune responses.

4. **Cellular Components**:
- **Neutrophils**: These are a type of white blood cell that responds quickly to sites of infection.
- **Monocytes**: These are larger white blood cells that differentiate into macrophages and dendritic cells when they migrate into tissues.
- **Macrophages**: These are derived from monocytes and play a crucial role in engulfing and digesting pathogens.
- **Natural Killer (NK) Cells**: These cells are part of the innate immune system and can kill virus-infected cells and tumor cells.

5. **Conclusion**: Both physical barriers (like skin and mucous membranes) and cellular components (like neutrophils, monocytes, macrophages, and NK cells) are integral parts of innate immunity. Therefore, the correct answer includes both options A and B.