What react to something foreign in the body such as germs bacteria and viruses?

Answer 1

The white blood cells react to recognise, engulf and destroy the invading cells.

There arw also lymphocytes and T-Cells and B-Cells which are activated with sensors so that Attatch to specific antigens. The T-Cells tell the B-Cell what shape antibody they need to attatch to the antigen on the invading cell. When all teh antigens on the invadingcell are sruck to a antibody the cell has been engulfed and destroyed. The cells also make copies(memory cells) of the antigens so that the will recognise and react fast as they already have the right antibodies prepared.

However - some virus' etc mutate (such as flu) so when this invades a second timethe antigens are different and the body doesn't recognise it and has to behin the process from start.

Answer 2

The immune system recognizes foreign invaders like germs, bacteria, and viruses by detecting specific molecules on their surface called antigens. This triggers an immune response where immune cells, such as white blood cells, produce antibodies to neutralize the threat. The immune system also forms memory cells to remember the invader, providing quicker and stronger response upon future exposure.