single
You can only have one but if you use two memory cards,you make one on each.
Game Files? There can only be one.
Backup files.
Downloading
You should only have one set of teeth
- incisor
The easiest way is to check Program Files folder. If you have two of them one is Program Files, another one is Program Files x86 then you have Windows x64, if you have only one Program Files, you have Windows x32.
No lower jawbone
A skull.
The descending structure between the front teeth is called the frenulum or frenum. Having a large or pronounced one is not unusual.
There are 28 teeth when you are a child and 32 teeth when you are an adult.You will only ever have 32 teeth if you take good care of them so,remember to brush.
.Zip is the only one i can think of.