Final answer:
Precocious puberty in African American and white females is considered to occur before 8 years old based on the average age of puberty onset. Factors such as genetics, environment, and nutrition can influence the age of puberty onset.
Step-by-step explanation:
For African American and white females, precocious puberty is considered to occur before 8 years old (option b) based on the average age of puberty onset in girls. Puberty typically begins in girls between the ages of 9 and 10 with the first visible changes being the development of breasts and pubic hair.
However it's important to note that the age of puberty onset can vary and is influenced by factors such as genetics, environment, and nutrition.