Which of the following can be described in terms of its states and properties?

Matter is indeed best described in terms of its states and properties. It encompasses everything that has mass and occupies space, which includes solids, liquids, gases, and plasma. Each of these states has distinct properties such as density, boiling point, melting point, and other physical characteristics. The description of matter incorporates both its macroscopic behavior (observable characteristics) and microscopic behavior (atomic and molecular structure).

Elements and compounds specifically refer to forms of matter, but they do not represent the overall concept of matter itself. An element is a pure substance made up of one type of atom, while a compound consists of two or more different elements chemically bonded together. While they can be described by their states and properties, they are subsets within the broader category of matter. An atom is even more fundamental, being the smallest unit of an element, and therefore does not encompass the various states of matter that the term 'matter' itself does.