What change to the following molecule's structure would result in a saturated fat?

It needs to gain a Hydrogen atom to eliminate the double bond between the two carbons.  

Explanation:

Unsaturated fat has one or more double bonds in its molecule. Saturated fat has a single bond. If you want an unsaturated fat to become saturated it needs to gain more more hydrogen atoms which will eliminate the double bonds between carbons of the unsaturated fat.

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