which best describes a mixture? it has a single composition, and it has a set of characteristics that does not change. it can have different compositions, but it has a set of characteristics that does not change. it has a single composition, but it has a set of characteristics that does change. it can have different compositions, and it has a set of characteristics that does change.

The correct statement is that it can exhibit different compositions, however, it has a set of characteristics that do not change.  

In science, mainly in chemistry, a mixture is formed when one combines two or more components and each of the components exhibits its own chemical characteristic. In order to consider as a mixture, the substances cannot dissociate or form chemical bonds with each other. To be a mixture, the substances must follow three usual characteristics, that is, they keep their own chemical properties, they can be easily distinguished, and the ratio of the components is variable.  

because u need two or more forms of the same element that contain equal numbers of protons but different numbers of neutrons in their nuclei to form isotopes.

so since they all have the same shape? i mean maybe because m& m and reeses are both chocolates