What defines a mixture?

A.

can be broken down into its basic substances through physical means

B.

described by a chemical formula

C.

cannot be broken down into simpler substances

D.

created through a chemical reaction

A. because a mixture can be physically separated by methods such as sieving, decantation, distillation, evaporation or filtering. For example a water+salt solution is a mixture and can be separated through evaporation.

A.

can be broken down into its basic substances through physical means