Bone remodeling in adults is regulated and directed mainly by (d) mechanical stress and (e) PTH
Work Step by Step
-(a) growth hormone is wrong because GH affects the growth of children and slows with aging. Once aging takes over it is mainly used for maintaining tissues and organs. -(b) thyroid hormones is wrong because it has nothing to do with bones remodeling. Just metabolism of food and muscles. So no dealing with bones. -(c) sex hormones are messengers for organs and cells and help our body's stay balanced. -(d) mechanical stress and (e) PTH are right through process of elimination.