Final answer:
GH directly promotes lipolysis in adipocytes, causing tissues to favor fatty acids over glucose for energy (glucose-sparing effect), and increases blood glucose levels by stimulating glycogen breakdown in the liver. However, in relation to the student's question, GH indirectly promotes bone growth through the activation of IGF-1.
Step-by-step explanation:
One direct action of growth hormone (GH) is its role in promoting the breakdown of triglycerides in adipocytes (fat cells) and the subsequent release of fatty acids into the blood. This leads tissues to switch from using glucose to fatty acids as an energy source, known as the glucose-sparing effect. Additionally, GH stimulates the liver to break down glycogen into glucose, raising blood glucose levels. This process is sometimes referred to as having a diabetogenic effect, due to its similarity with high blood glucose levels seen in diabetes mellitus.
Despite having both direct and indirect actions, for the purpose of answering the student's question, option (a) 'Promoting cell division in bones' is the best match because GH indirectly stimulates the growth of bones by activating insulin-like growth factors (IGFs), particularly IGF-1, which in turn leads to the production of bone cells or osteocytes.