Answer:
mixture
Step-by-step explanation:
Chromatography separates components of a material based on their difference in polarity. Since the chromatography experiment resulted in more than one mark appearing, there must be more than one component in the material.
Upon standing for 24 hours, the liquid ink separates into its different components based on their differing properties, such as density or solubility. Since a pure substance is homogeneous and has the same properties throughout, the ink cannot be a pure substance.