IMMUNOLOGY

Detailed explanation-1: -Answer and Explanation: Fever is not the first line of defense; it is considered the second line of defense. Suppose the first line of defense couldn’t protect the body, and the pathogen still enters the body. In that case, the second line of defense protects the body, including fever, inflammation, and phagocytosis.

Detailed explanation-2: -Neutrophils. They kill and digest bacteria and fungi. They are the most numerous type of white blood cell and your first line of defense when infection strikes.

Detailed explanation-3: -The second line of defense includes nonspecific cells and chemicals that work within the body to identify foreign pathogens and kill the invaders. These nonspecific cells are found in the bloodstream and are types of white blood cells, which are also known as leukocytes.

Detailed explanation-4: -The first line of defence (or outside defence system) includes physical and chemical barriers that are always ready and prepared to defend the body from infection. These include your skin, tears, mucus, cilia, stomach acid, urine flow, ‘friendly’ bacteria and white blood cells called neutrophils.

Detailed explanation-5: -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-6: -The second line of defense is nonspecific resistance that destroys invaders in a generalized way without targeting specific individuals: Phagocytic cells ingest and destroy all microbes that pass into body tissues. For example macrophages are cells derived from monocytes (a type of white blood cell).