Very generally speaking, the firearm was invented so people could have an advantage when fighting against someone with a sword or spear. With a sword or spear or any other contact weapon, you must be very close to the person you are attacking. With a firearm you can hit an attacker from 20 yards or more away.
Firearm - comics - was created in 1993.
The Chinese created the first firearms.
A shotgun is a firearm. A revolver is a firearm. A pistol is a firearm. A rifle is a firearm. If you want even more specific -- A Remington 1187 is a firearm (shotgun). A Smith and Wesson 686 is a firearm (revolver). A Sig Sauer P226 is a firearm (pistol). A Colt 6920 is a firearm (rifle).
No, Sword is not a firearm.
Design of the firearm
Warrior + firearm
yes
No, he cannot have a firearm.
That depends if you are talking about the firearm or about the cartridge.
I saw a firearm.
Condition of firearm and how desperate you are.
Yes, a shotgun is classified as a firearm.