Related to biodiesel synthesis. In regards to biodiesel purification and liquid-liquid extraction. Please answer these questions.

Background info. Measuring viscosity: Samples are Ethanol, Methanol, Vegetable oil, Commercial biodiesel pure sample, Glycerol pure sample, and glycerol layer from the reaction.
Data: The times elapsed from measurements of viscosity; Ethanol (6.22 sec), Methanol (2.09 sec), Glycerol (over 8 min), vegetable oil (49.60 sec), commercial biodiesel (4.16 sec), and Glycerol layer from reaction (2.28 sec).

Did the viscosity of pure samples match that of your synthesized biodiesel layers? Comment on what this means for the success of your purification method

Why was it important to do a good job on your liquid-liquid extraction of biodiesel (the fuel for a car engine) considering glycerol is a by-product of the synthesis?