Main barrier which prevents the entry disease's causing organism in our body is/are

Options

A. Skin
B. Saliva
C. lumphocytes
D. Interferons

Answer

### Step-by-Step Solution:

1. **Understanding the Question**: The question asks for the main barrier that prevents disease-causing organisms from entering our body.

2. **Identifying the Barriers**: The body has several types of barriers that protect against pathogens. These include:
- **Physical Barriers**: Such as skin.
- **Physiological Barriers**: Such as saliva, tears, and stomach acid.
- **Cellular Barriers**: Involving white blood cells (WBCs) like neutrophils.
- **Cytokine Barriers**: Such as interferons that help in cell communication during infections.

3. **Focusing on the Main Barrier**: Among all these barriers, the skin is the first line of defense that pathogens encounter when they try to enter the body. It acts as a physical barrier.

4. **Conclusion**: The main barrier that prevents the entry of disease-causing organisms into our body is the **skin**.

5. **Final Answer**: The correct answer is **A. Skin**.