Final answer:
Steroids are lipids with a structure of four fused carbon rings, exemplified by cholesterol, and are hydrophobic and insoluble in water.
Step-by-step explanation:
​Steroids are a group of lipids whose carbon skeletons contain several fused rings. Unlike phospholipids and fats, steroids are characterized by this unique structure, which consists of four linked carbon rings. They are classified as lipids because they share the common property of being hydrophobic and insoluble in water. An example of a steroid is cholesterol, which has a short tail and, in many cases, an -OH functional group that classifies it as a sterol.