Which of the following statements are true about measurements and units? a. the si unit system is used by scientists all over the world.b. measurements must include numerical values and units.c. the si system is based on powers of ten.d. the unit of mass in the si system is the pound.

  B. Solution

Explanation:  According to the question statement, Susan wrote in her notebook that it was a blue liquid. Therefore, from a chemistry point of view, it was a solution and not a heterogeneous mixture. Then, the solvent was evaporated after leaving the solution for 72 hours at the windowsill. The solute (blue color most likely) however was not able to evaporate with solvent and left behind.

Example: if you leave the KMnO4+water solution for a few days, water will evaporate thus leaving behind purple crystals of KMnO4.