Ans.
Liver helps to keep the blood sugar in a constant level by different means. When blood sugar level increases, liver cells increase glucose uptake due to influence of insulin hormone and thus, decrease sugar level in blood. When sugar level decreases, liver cells show gluconeogenesis and add sugar into the blood due to the action of glucagon hormone, and thus, increase blood sugar level.
As homeostasis is a mechanism that involves maintenance of constant internal conditions, and liver shows maintenance of constant sugar level in body, the correct answer is 'option a).'