To protect valuable assets. Some fighters are more expensive.
absolutely nothing except underwear
I have absolutely no idea!
no
Absolutely essential
No. It is absolutely not necessary. But it is a Sunnah to do so.
Absolutely
Absolutely necessary.
Absolutely not.
imperative crucial
Unnecessary
Estrogen
Armor of all types was necessary in the ancient world for protection, just as our present day "flack jackets" are needed for protection.