The executive branch is composed of the President, Vice President and Cabinet members. President The president is the head of state, head of the U.S. government and the commander-in-chief of the U.S. military.
Menarche. The average age of menarche, or first menstruation, in the United States is 12.88 years for Caucasian girls and 12.16 years for African American girls. A popular misconception is that menarche marks the beginning of puberty; in reality, menarche occurs later in puberty.
The analysis of over ten thousand histories in the United States and Canada by Engelmann showed that the average age at which menstruation begins (menarche) is 13.9 years. [Footnote:] The question of early maturity is not so much one of [geographic] latitudes of the immediate environment of clothing and house heating.ecline in the age of appearance of the menarche during recent decades, from roughly 17 years in 1830 to less than 13 years a century and a half later.. The chart comes from Holland, but probably generally applies to America and western Europe. That line looks too straight to be true.