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.
Mexican-American women decreased by 12 months from. the pre-1920 cohort to the 1980 â1984 cohort, by almost 10. months for whites, and by almost 15 months for blacks. All. decreases were statistically signiï¬cant. They concluded, âSigniï¬cant declines in the mean age of menarche for US. females occurred. . .â [1]. In research on this topic, one of three methods may be. usedâlongitudinal studies, and for cross-sectional studies, the status quo method or retrospective inquiry.