Explain the mechanism of functioning of vaccines.

Explanation

**Step-by-Step Solution:**

1. **Understanding the Immune System**: The human body has a natural immune system that protects against infections. This system is crucial for identifying and combating foreign invaders like bacteria and viruses.

2. **Role of Lymphocytes**: When a foreign antigen (such as a virus or bacteria) enters the body, specialized immune cells called lymphocytes are activated. These cells are responsible for producing antibodies.

3. **Antibodies Explained**: Antibodies are proteins that specifically target and neutralize foreign antigens. They play a vital role in the immune response by binding to pathogens and marking them for destruction.

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