Official websites use .gov
A
.gov website belongs to an official
government organization in the United States.
Secure .gov websites use HTTPS
A lock (
) or https:// means you've safely
connected to the .gov website. Share sensitive
information only on official, secure websites.
Example of a growth curve of sitting height of an individual girl. The grey line is the derivative of the growth curve, i.e. the growth velocity curve. The vertical black line represents the age of the peak growth velocity of sitting height of this particular child
