Just as on the demand side, the position of the supply can shift, say from a change in the price of a productive input or a technical improvement. The Law of Supply states that, in general, a rise in price leads to an expansion in supply and a fall in price leads to a contraction in supply.
Puberty takes place over a number of years, and the age at which it starts and ends varies widely. It generally begins somewhere between the ages of 7 and 13 for girls, and somewhere between the ages of 9 and 15 for guys, although it can be earlier or later for some people.
Average Age Of Growth Spurts In Boys. The average age at which puberty begins in boys is 11 to 12 years. The end of puberty is not clearly delineated and may vary with the physical, emotional, mental, social and cultural criteria to define an adult boy. However, it usually gets complete at around the age of 17 to 18.