Our health is influenced by personal characteristics, environment, and lifestyle. Unhealthy habits and an unsafe environment can encourage illness, while healthy habits and a good healthcare system make illness less likely. There are infectious illnesses caused by viruses, bacteria, fungi and protozoa, and non-infectious illnesses like diabetes. Some key behaviors for maintaining health include eating a balanced diet, practicing good hygiene, engaging in physical activity, and avoiding risks like smoking, drugs and excessive technology or alcohol use. Proper food hygiene, vaccinations, medical checkups and preventative measures can also keep people healthy.