Which phrase best describes an apple:
An apple is obviously not a pure substance. It is made up of numerous chemicals in both the pulp and the juice (water, vitamins, minerals, sugars, etc). It also consists of different phases or mediums such as the pulp, juice, skin, and core. So let's look at each choice individually.
Heterogeneous mixture: An apple is a mixture of several chemical compounds. It is also heterogeneous in the fact there are different phases containing different chemicals. This seems promising.
Homogeneous compound: This would imply that an apple is a single chemical compound and it is uniformly distributed as a single phase. This does not apply to an apple.
Heterogeneous substance: As stated before, heterogeneous is correct here but the term substance usually denotes a distinct chemical compound that cannot be separated into different chemical entities. This does not apply to an apple.
Homogeneous mixture: An apple is a mixture of compounds but that mixing is not homogeneous (single phase). So this does not apply either.
By process of elimination, we can see that an apple is best described as a heterogeneous mixture.