Final answer:
Insulin inhibits lipolysis in adipocytes, thereby preventing the breakdown of triglycerides into glycerol and fatty acids and aiding in the regulation of blood glucose levels.
Step-by-step explanation:
Insulin is a hormone secreted by the pancreas that plays a crucial role in regulating blood glucose levels by facilitating the uptake of glucose into cells and promoting its storage as glycogen in the liver and muscle cells. One of the actions of insulin on adipocytes, or fat cells, is to inhibit lipolysis, which is the breakdown of triglycerides into glycerol and fatty acids. Therefore, the correct answer to the question of what insulin acts on adipocytes to do is B. Inhibit lipolysis.
Additionally, insulin also has other functions such as stimulating glycolysis and fat synthesis, while inhibiting glycogenolysis and gluconeogenesis.