Final answer:
It is true that pubertal developments such as the first menstruation, or menarche, are tied to body weight in females. Factors like body fat are necessary for the onset of menstruation, and the average age for menarche in the U.S. is 12.4 years, although there is considerable variation.
Step-by-step explanation:
Pubertal developments such as first menstruation, more formally known as menarche, are indeed tied to body weight in females. This is true. A certain amount of body fat is necessary for the onset of menstruation, which is a part of puberty. During puberty, girls experience a number of significant changes, including menarche, which typically occurs at an average age of 12.4 years in the United States, with a normal range between eight and 16 years old. The start of menstruation signifies that the female's body has begun to ovulate, which means the ovaries are releasing eggs periodically.
Another factor impacting the timing of menarche is the rapid increase in height and body mass that occurs during the growth spurt of puberty. Girls are expected to grow about 3 inches per year during this period. Moreover, genetic and environmental factors, such as nutrition, contribute to the variation in the age at which menarche occurs. Overall, body weight and other environmental factors play a significant role in determining when a girl will experience her first menstruation.