What feature distinguishes Type 1 from Type 2 diabetes?

Type 1 diabetes is primarily characterized by insulin deficiency due to the autoimmune destruction of the pancreatic beta cells, which produce insulin. This leads to an absolute lack of insulin, necessitating external insulin administration for survival. In contrast, Type 2 diabetes generally involves insulin resistance and may present with sufficient or even elevated levels of insulin initially, but the body's cells do not respond effectively to it.

The other options are related to different aspects of diabetes mellitus. Ketosis can occur in both types but is more commonly associated with the insulin deficiency seen in Type 1 diabetes, especially during periods of illness or lack of insulin. It's important to note that Type 2 diabetes typically develops in adults, but it can also occur in children due to rising obesity rates. Lastly, while Type 1 diabetes is associated with autoimmune disorders, Type 2 diabetes is generally linked to metabolic syndromes rather than autoimmune processes. Each of these points highlights the distinguishing features of the diabetes types, supporting the view that insulin deficiency plays a critical role in defining Type 1 diabetes.