This article talks about how scientists are studying how our bodies make important fatty acids called PUFAs. They found out more about the machines that create these fatty acids. These machines have different parts that each make a specific type of PUFA. By doing experiments, they figured out how these machines decide which type of PUFA to make. They also changed one machine that usually makes one type of PUFA into a machine that can make a different type. This means that they are getting better at understanding and controlling how our bodies make these important fats.