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What is 1 + 3?
A measure of the amount of matter in an object.
A measure of how gravity pulls on an object.
Any of a group of elements that conducts heat and electricity, has a shiny luster, and is flexible.
The center of an atom that has most of its mass.
A particle in the nucleus of an atom that carries one unit of positive electric charge.
A particle in the nucleus of an atom that has no electric charge.
A particle in the space outside the nucleus of an atom that carries one unit of negative electric charge.
A particle that contains more than one atom joined together.
The ability to be pulled into thin wires without breaking.
The gradual wearing away of a metal by combining with nonmetals in its environment.
A measure of how much space the matter of an object takes up.
A material that has properties in between conductors and insulators.