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.
Environmental influences also affect the onset of menstruation. Delayed menarche is associated with excessive exercise, malnutrition, and significantly low weight. Sports or other activities that require intense physical activity, such as dancing and gymnastics, are associated with later ages at menarche. Such processes, however, can be reversed.