Question

type 2 diabetes mellitus is primarily a problem with
lack of insulin production
decreased sensitivity to insulin by cells
abnormal insulin molecules
liver failure.

Explanation:

Type 2 diabetes mellitus is mainly due to insulin - resistance, where cells have decreased sensitivity to insulin, rather than lack of insulin production (which is more typical of type 1 diabetes), abnormal insulin molecules, or liver failure.

Answer:

decreased sensitivity to insulin by cells