Explanation: When you heat a sample of gas, the particles move faster to the particles that make up the gas.When heat is added to a substance, the molecules and atoms vibrate faster. As atoms vibrate faster, the space between atoms increases. The motion and spacing of the particles determines the state of matter of the substance. The end result of increased molecular motion is that the object expands and takes up more space.Mass of the object remains the same, however solids, liquids and gases all expand when heat is added.Hence, the correct option is (A).