RussiaUS
America has the most nuclear weapons
126 Countries The most known is of course Russia (earlier sovjet) and USA :-) You probable mean Bio-Chemical weapons ;-)
Most did their own independent development.
USRussiaUKFranceChinaIndiaPakistanNorth Korea
Most countries have zero nuclear weapons.
Chemical weapons and DDT.
"Arms Race"
they dont make their own weapons they just buy them of other countries but most likely ak-47 is the most popular weapon in peru
An "arms race".
Very difficult to answer - since most countries are extremely secretive about the amount of nuclear weapons they have stockpiled.
IR is called an "arms race".