Burglars can commit rapes, robberies, and assaults if they are surprised by someone coming home or pick a home that is occupied.
At night, if you think you hear someone breaking in, leave safely if you can, then call police. If you can't leave, lock yourself in a room with a phone and call police. If an intruder is in your room, pretend you are asleep.
Guns are responsible for many accidental deaths in the home every year. Think carefully before buying a gun. If you do own one, learn how to store it and use it safely.
If something looks questionable - a slit screen, a broken window, or an open door - don't go in. Call the police from a neighbor's house or a public phone.