If you have not already done so, download Avogadro for free and watch the tutorials if necessary.
Open two work paper in Avogadro and import the structures of the palmitic and of the stearic acid (sequence Build → insert → fragment).
Check the molecules and, by studying the (sequence Wiew → properties), say why palmitic acid is harmful and stearic acid is not.
Therefore, highlight the main properties of the structure of the molecule.