Watch the link below, and take notes on the hormones that control bone growth.
http://www.bing.com/videos/search?q=khan%20acedemy%20skeletal%20bone%20growth&qs=n&form=QBVR&pq=khan%20acedemy%20skeletal%20bone%20growth&sc=0-22&sp=-1&sk=#view=detail&mid=B0F47530764870EA0E3BB0F47530764870EA0E3B
http://www.bing.com/videos/search?q=khan%20acedemy%20skeletal%20bone%20growth&qs=n&form=QBVR&pq=khan%20acedemy%20skeletal%20bone%20growth&sc=0-22&sp=-1&sk=#view=detail&mid=B0F47530764870EA0E3BB0F47530764870EA0E3B