Today eight countries are possessing nuclear weapons. The five nuclear weapons states United States, Russia (former Soviet Union), United Kingdom, France and China, are the only countries allowed to have nuclear weapons according to the Non-Proliferation Treaty (NPT) from 1970.All members of the United Nations except Israel, India and Pakistan have signed the NPT.he five nuclear weapons states United States, Russia (former Soviet Union), United Kingdom, France and China, are the only countries allowed to have nuclear weapons according to the Non-Proliferation Treaty (NPT) from 1970. All members of the United Nations except Israel, India and Pakistan have signed the NPT.
User: The most common form of matter in the universe is _____. plasma gas liquid solid. Weegy: The most common form of matter in the universe is PLASMA. User: The state of matter with a specific volume but no definite shape is the _____ state. plasma gas liquid solid. Log in to see more information.
The most common compound is water. Its molecule is made up of two hydrogen atoms and one oxygen atom. Hydrogen is the most common atom in the universe, and oxygen is the thrid â¦ most common, so water has to be the number one compound.289, 758.)   However water is the most common substance on the surface of the  Earth.   In the atmosphere, Nitrogen is the most common element (78%).