Here's why:

* Lipids are a diverse group of biological molecules that are characterized by being hydrophobic, meaning they don't dissolve in water.

* Fatty acids are long chains of carbon atoms with a carboxyl group at one end. They are a key component of many different lipids, including:

* Triglycerides: These are the main form of fat storage in the body.

* Phospholipids: These form the cell membrane, creating a barrier between the inside and outside of cells.

* Steroids: These include hormones like cholesterol and testosterone.

So, while fatty acids are not the only component of lipids, they are a fundamental building block and are essential to their structure and function.