Answer:
The component of the feedback system broken in these individuals is the effector.
Step-by-step explanation:
The stimulus is increased blood glucose level, sensors sense the presence high blood glucose level, while the response is the secretion of insulin by the beta-cells in the Islands of Langerhans, then it acts on effector and stimulates to take glucose into the cell.
In the scenario given, the response till the insulin secretion is normal, but the cells ( effector ) is not taking the glucose into the cell so the effector in the feedback system is affected.
Therefore, the component of the feedback system broken in these individuals is the effector.