The purpose of introducing weakened microbes into the body is to stimulate the immune system.

Here's why:

* Weakened microbes (vaccines): These microbes are either dead or have been significantly weakened so they cannot cause the full-blown disease.

* Immune system response: When introduced into the body, the immune system recognizes these weakened microbes as foreign invaders.

* Memory cells: The immune system then mounts an immune response, producing antibodies and memory cells specific to that particular microbe. These memory cells are crucial because they allow the body to quickly recognize and fight off the real pathogen if ever exposed to it in the future.

This process is called vaccination, and it is one of the most effective ways to prevent infectious diseases.