Answer: D. The characteristics of the mixture change within a sample.
Step-by-step explanation: Homogeneous mixture are those mixtures in which dispersed phase is uniformly distributed throughout the dispersion medium and thus the composition is same throughout. There is no physical distinction between the dispersed phase and dispersion medium. Example: Salt in water
Heterogeneous mixture are those mixtures in which dispersed phase is not uniformly distributed throughout the dispersion medium and thus the composition is not same throughout .There is a physical distinction between the dispersed phase and dispersion medium. Example : Oil in water