Answer:
1.
A saturated fatty acid (i.e., an alkyl-chain fatty acid) with two or more ethylenic carbon–carbon double bonds; because of the double bond, not every carbon is saturated with hydrogen atoms—i.e., there are fewer hydrogens—which reduces the strength of the compound's intermolecular forces, resulting in a significant lowering of the compound’s melting point.
2. fatty acids (PUFAs) are fatty acids that contain more than one double bond in their backbone
Explanation:
