yes
no
Firearms are objects. They have no more legal standing than your armchair. In certain countries firearms are legal in others there are restrictions on the type of firearms citizens may own. It depends on the legislation of the country you are referring to
No, they cannot.
Yes, in accordance with the provisions of the National Firearms Act of 1934.
Depens on where you are. In the US, ordinary citizens may own semi-auto firearms, an in most states, fully automatic firearms (machine guns). They are required to be registered with the BATFE, and a transfer tax paid when fist buying one. They are VERY expensive, but legal. In other countries, other laws.
Depends on what you mean by automatic guns, and the law where you live. You did not tell us where that is, so there is no way we can answer. Where I live you CAN legally own fully automatic firearms (machine guns) but they are horribly expensive. An M16 rifle that may be owned by a private citizen is between $12,000 and $16,000.
Not everywhere. In the US, law abiding adults have the right to own and use firearms. This is guaranteed both by various state laws, and by the 2nd Amendment to the US Constitution.
The short answer is no, unless you have a firearms collector's licence. A fully automatic weapon is a restricted weapon and unless you have the correct licence you are not allowed to import them or own them. The collector's licence is difficult to get and restrictive.
In typical combat situations any soldier killed dies with his own weapons, or the weapons issued to him by his combat unit.Only rarely do people kill themselves with their own weapons, though suicide with one's own firearms is more common than suicide with someone else's firearms.
Firearms have not been banned. but groups of people have been trying to ban them because some people actually believe that making it illegal to own an object will reduce crime or change the way people behave.
yes you can have guns at age 18. the only guns you can legally own though are shotguns and rifles that are single shot or bolt action or lever action or something like that. at age 21 you have to get a class 3 firearms license to legally purchase and own fully automatic firearms and pistols. but before that yes you can own shotguns and rifles and it is legal