Which statement correctly describes isomers?

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Isomers share the same molecular formula but have different structural arrangements. This captures the essence of isomerism: molecules can have identical counts of each atom yet differ in how those atoms are connected or arranged in space. Structural (constitutional) isomers differ in connectivity, while stereoisomers have the same connectivity but a different three-dimensional arrangement. Enantiomers are a special subset of stereoisomers that are non-superimposable mirror images, but not all isomers are enantiomers. Because the arrangement of atoms changes how atoms interact, isomers often exhibit different physical properties, such as boiling or melting points. For example, butane and isobutane have the same formula C4H10 but different connectivities, illustrating structural isomerism.