yes
No, but most do today. For one thing or another. Even the least expensive disposable film camera will have a small battery for the built-in flash if it has one. Any cameras with electronics will need some kind of battery. But some cameras, even incredibly good ones, don't need any. They are considered "mechanical" only.
They may not sell batteries that are not in production any longer, but a battery retailer such as them should be able to special-order any type of battery that is in production for you.
Any battery socket that it fits.
any brand of battery works, but you have to have the right kind of battery.
No. A battery charger has to be specifically matched to the batteries to be charged.
Any place that sells batteries will take your old battery.
you can buy batteries at almost any store, such as Walmart, Radioshack, Walgreens, Domincks, leoch battery etc.
They work on many pieces of home equipment that require batteries, such as laptops, camcorders, and digital cameras. It just depends on what types of batteries you've picked up.
Any place that sells batteries can tell you what size battery to purchase.
Panasonic does not manufacture batteries for older cameras any longer, however that does not mean the batteries can not be found. Online retailers such as Amazon still carry old batteries from sellers who no longer need them.
They store energy - that's the basic purpose of any battery.
Apple uses Lithium Ion batteries, arguably the best battery you can buy. Any battery you get from an authorized dealer will be the same Apple uses, and any that are not authorized are likely to be dangerous, or at least lower quality.