Carbohydrates serve as an energy source or have structural roles. These simple sugars are soluble in water and may be sweet-tasting. These are also made from glucose molecules, but they are stuck together in different ways. Also imporatant in insulation from heat-loss and for cushioning important organs. They are non-polar so they are hydrophobic.
Oils are lipids that are liquid at room temperature.
A fatty acid is a long, unbranched chain of Cs and Hs with an acid group at the end. The double bo nds in unsaturated fatty acids create kinks in the carbon chain. These kinks allow these types of oils to stay liquid at room temperatures. Phospholipids are a special class of lipids that have a glycerol, only two fatty acids, with the third lipid substituted for by a phosphate group. These are important components of cell membranes.