In the immune response, the phase in which killer t cells strike at foreign cells and at cells of the body that have been invaded and infected is called

Cell mediated immune response

Explanation: The immune response could be either humoral or cell mediated. Humoral is use of antibodies to kill the pathogens and infection. In cell mediated immune response, immune cells like T cells, phagocytes, etc are used to kill the pathogens or infected cells. Killer T cells get activated when they get signal from other proteins of the immune system.

geologic time scale (for gradpoint) =)