How would one describe the difference between saturated and unsaturated hydrocarbons and what is the distinguishing feature of aromatic hydrocarbons?

Unlike saturated hydrocarbons in which all hydrogen atoms and carbon atoms are bonded together with single bonds, unsaturated hydrocarbons have double or even triple bonds between the carbon atoms. This makes unsaturated hydrocarbons even more reactive than saturated hydrocarbons, as well as have fewer hydrogen atoms bonded to the carbon atoms than saturated hydrocarbons have.