Research on the onset of puberty has revealed that
A)the average age of menarche now occurs at about 15 years old.
B)the average age at puberty is increasing in Europe and North America.
C)menarche depends on a critical level of body fat.
D)There is little variability in the onset of puberty.

Question

Quizplus · Accepted Answer

Research has shown that menarche, the onset of menstruation, is influenced by a critical level of body fat. Girls need to have a certain amount of body fat before they can start menstruating. This is why girls who are undernourished or have low body weight tend to experience puberty later. The average age of menarche varies by race and ethnicity, but in the United States, it typically occurs between the ages of 12 and 13. The age of puberty onset is also affected by environmental factors, such as exposure to endocrine-disrupting chemicals.

Research on the Onset of Puberty Has Revealed That