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.
Because long cycles most often occur in the first 3 years postmenarche, the overall trend is toward shorter and more regular cycles with increasing age. By the third year after menarche, 60% to 80% of menstrual cycles are 21 to 34 days long, as is typical of adults.