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.
Male Growth Patterns. Boys generally hit their growth spurt about two years after girls, according to KidsHealth.org. Most boys grow most quickly between ages 12 and 15 and stop growing by age 16, but this depends on when they reach puberty. Boys usually continue developing muscles and gaining weight after they stop growing taller. The average adult male in the United States is about 69 inches tall, according to the CDC.