The correct answer is mixtures.
Salt water, vinegar, bronze, air, and beach sand are all mixtures, some of them more homogeneous or heterogeneous than others. A mixture, as the name itself says, is a blend of more than one element. So salt water is a mixture of salt and water, vinegar is a mixture of acetic acid and water, bronze is a mixture of copper and other metals, air is a mixture of nitrogen, oxygen, and other elements, and beach sand is a mixture of sand and water.
