Here's why:

* Origin: Insulin is a protein hormone naturally produced by the pancreas in living organisms (specifically, the beta cells of the islets of Langerhans).

* Structure and Function: It has a complex structure and plays a vital role in regulating blood sugar levels, a key metabolic process essential for life.

* Production: Insulin used for medical purposes (like for people with diabetes) is often produced through recombinant DNA technology, which involves using living cells (bacteria) to synthesize the protein.

While insulin can be produced through bioengineering, its fundamental origin and function are biological.