Hormonal Regulation in Plants and Animals: Form and Function

Which hormone is primarily responsible for stimulating bone growth and development in humans, as illustrated by the difference in skeleton size between the adult and child in the image?

The image shows two skeletons of different sizes. Which feedback mechanism is most likely involved in regulating the secretion of the hormone responsible for growth?

If the smaller skeleton in the image represents a child with a deficiency in growth hormone, which of the following would be a likely physiological consequence?