The first part of the immune system to attack an invader is B. Macrophages.
Here's why:
1. Macrophages are part of the innate immune system, which acts as the first line of defense against pathogens.
2. When an invader enters the body, macrophages are among the first immune cells to respond.
3. Macrophages engulf and digest foreign substances, such as bacteria or viruses, helping to prevent infection and activate the adaptive immune response.
4. They also play a crucial role in presenting antigens to other immune cells like T cells and B cells, initiating a more targeted and specific immune response.
In summary, macrophages are the front line of defense in the immune system, recognizing and eliminating invaders to protect the body from infection.
