<prompt> Prostaglandins are obtained from:-Stearic acidArachidonic acidLinoleic acidLinolenic acid  <response>: NOTE:-Arachidonic Acid is a 20 carbon fatty acid. No.of double bonds in Arachidonic acid 4 Key points to Remember Linoleic Acid- Most essential Fatty Acid. Richest source of linoleic Acid - Safflower oil. Richest source of Arachidonic Acid - Safflower oil. Richest source of Linolenic Acid - Flaxseed oil. 