What are the two levels of the body's defense mechanisms against pathogens?

1. The Local Defence System
2. The Immune System.

Describe the role of white blood cells in the immune response.

White blood cells engulf and destroy germs through a process known as phagocytosis.

What is the main function of antiseptics?

Antiseptics are mild chemical substances that kill germs when applied to the body.

Riddle: I am a strong chemical that kills germs on surfaces but I can't be used on skin. What am I?

A disinfectant.

What distinguishes passive immunity from active immunity?

Passive immunity is received from an outside source, while active immunity is produced by the individual's own body.

What is the significance of World AIDS Day?

World AIDS Day is observed to raise awareness about the seriousness of AIDS and the protective measures available.

How does the skin act as a protective mechanical barrier?

The skin is made of keratin, which is largely impermeable to germs; it also helps prevent entry through cuts and scrapes.

What type of immunity is provided by vaccinations?

Vaccinations induce active immunity by introducing killed germs or germ substances to stimulate the production of specific antibodies.

List two examples of germ-killing secretions in the human body.

Saliva and hydrochloric acid.

True or False: Antigens are produced by the immune system to fight off pathogens.

False. Antigens are chemicals found on the surface membranes of germ cells.

What are the primary methods the body uses to expel germs or foreign particles?

Coughing, sneezing, and vomiting.