For support, to look "sexy", coverage for when they are "nipping", to make them look bigger, to give them more shape, to push them up, to hold them in place, etc....
Yes
most American women do
bra & penty
Typically the users of a bra are women although not all women wear them. Sometimes men would like to have support.
You can wear a bra when you go outside, in fact most women do. You cannot (or at least should not) wear it outside as your primary piece of clothing.
no they were not around at the time
No, because women wear bra to look their breast more comfortable, tight, big and sexy.
Not enough :(
Support bra which women wear while excersizing also called sports bras
Home made T-shirt
No. Bras hold up women's boobs. Guys don't have boobs. They shouldn't need a bra.
Some girls like to wear no bra and underwear because they like the freedom of not feeling restricted in tight fitting undergarments.