What is the primary characteristic of type 2 diabetes mellitus?

The primary characteristic of type 2 diabetes mellitus is indeed poor lifestyle choices leading to insulin resistance. Type 2 diabetes often develops when the body becomes resistant to insulin or when the pancreas is unable to produce sufficient levels of insulin to maintain normal glucose metabolism. Factors such as obesity, sedentary lifestyle, and poor dietary habits contribute significantly to the development of this condition, which is typically seen in adults but can also affect children in the context of rising obesity rates.

This option accurately reflects the complex interplay between lifestyle factors and the body's response to insulin. On the other hand, type 2 diabetes is not characterized by a complete inability to produce insulin, as individuals with this condition may still produce some insulin but not enough to overcome the resistance their bodies have to its effects. Moreover, type 2 diabetes can affect people of all ages, not just children and adolescents, and it does not always require insulin injections for management, especially in the early stages, as many patients can be managed through lifestyle changes, oral medications, and other therapies.