IMMUNOLOGY

Detailed explanation-1: -The second line of defence is a group of cells, tissues and organs that work together to protect the body. This is the immune system.

Detailed explanation-2: -Innate immune cells are the body’s first line of defense. They quickly respond to foreign cells to fight infection, battle a virus or defend the body against bacteria. T-cells and B-cells react when invading organisms slip through that first line using a process called acquired immunity (or adaptive immunity).

Detailed explanation-3: -Second line of defense An inflammatory response begins when a pathogen stimulates an increase in blood flow to the infected area. Blood vessels in that area expand, and white blood cells leak from the vessels to invade the infected tissue. These white blood cells, called phagocytes engulf and destroy bacteria.