most likely a valve oring in damaged.
It depends on the gun, but "both" is an acceptable answer.
Co2 comes out of a bb gun because of the compressed co2 cartridges that are used to propel the bb itself. Additionally, the bb gun that does not use co2 cartridges just doesnt shoot out co2, but air in general.
Do a search on the web for "Air gun repair" and locate a shop near you to repair the air gun, or See the link below.
Try a large well stocked air gun shop.
The CO2 Guns are usually used for Paintball games or for Party effects. One can buy them at eBay, Air Gun Depot, Air Gun Buyer, Palco Sports, Pyramid Air and many more.
If by drop you mean it drops quickly in air when fired, then yes, your gun is almost out of CO2.
An air-soft gun that is powered by CO2 or green or red gas instead of a spring or a battery.
No you do not need to put air in an airsoft gun. These guns are either spring powered where you must cock the gun before you shoot it, electric powered which are automatic and require batteries, or CO2 powered which requires a CO2 cartridge. This CO2 is not expensive and a pack of 40 CO2 cartridges costs only 20-25 dollars. the guns that require CO2 are not as common as the other forms of airsoft guns, although they are more powerful. In general, if you buy an airsoft gun, you do not need to put any air into it.
Not always but Yes. If it hits a vital spot. Never point an air gun at another person.
I would start by checking the web under "Air Gun Repair" or see the link below.
You simply screw the CO2 into the back of the gun. Unless your CO2 should go elsewhere which is different to each gun.