Here are some quick tips on how to distinguish classic crystal from plain glass. 1  Hold up a glass to the light. 2  If the glass acts as a prism and you see a rainbow you are holding crystal.
Growth is a very complex process, and requires the coordinated action of several hormones. The major role of growth hormone in stimulating body growth is to stimulate the liver and other tissues to secrete IGF-I. IGF-I stimulates proliferation of chondrocytes (cartilage cells), resulting in bone growth.
Hormones are kind of the same thing. Your glands add them to your body -- like a special ingredient -- so you can grow up. In girls, puberty is controlled by the hormones estrogen and progesterone. In boys, puberty is controlled by a hormone called testosterone.