Health is defined as a state of physical and mental well-being, while illness is the opposite of health. The document discusses maintaining health through healthy habits like getting enough sleep, eating a balanced diet, and washing hands regularly. It also explores different types of illnesses like infectious and non-infectious diseases. Infectious illnesses can be caused by microorganisms like bacteria, viruses, fungi, and amoebae. The document recommends preventing infections through practices like disinfecting wounds, washing hands before eating, and avoiding sharing utensils. Vaccines can provide protection against some viral and bacterial illnesses by exposing the body to weakened forms of pathogens. Treatment depends on the cause, with antibiotics used for bacterial infections