Identify a true statement about the onset of menstruation, termed "menarche."

A) There is a great deal of consistency and predictability in its timing.
B) European American girls reach menarche earlier than African American girls do.
C) Latina girls reach menarche several months later than Asian American girls do.
D) It occurs at about 12½ years of age on average.

The onset of menstruation, or menarche, occurs at about 12½ years of age on average. While there may be some variation in timing due to genetic, nutritional, and environmental factors, there is not a great deal of consistency and predictability in its timing. Ethnicity can also play a role in the timing of menarche, with African American girls typically reaching menarche earlier than European American girls, and Latina girls reaching menarche at a similar age to European American girls. There is no evidence to suggest that Asian American girls reach menarche several months later than Latina girls.