Diet and exercise also have an important part to play in keeping us fit. Obvious factors such as drug abuse, smoking and alcohol are contributory factors towards poor health. Our food, if not cooked properly, can make us ill. Living conditions are also important. Microbes breed quickly in water.
Contaminated water has to be boiled before it can be drunk.
Contact - close contact with a person or animal infected with a microbe can spread this to other people. Coughing and sneezing sprays droplets of moisture into the air containing microbes which are then breathed-in by others. Flies and rats also carry diseases. This section tends to be tested in the Higher papers . Antibodies are very clever.