Final answer:
In comparison to the late 1800s in the United States, today the period of adolescence is longer and more complex.
Step-by-step explanation:
The correct answer is a) longer; more. In comparison to the late 1800s in the United States, today the period of adolescence is longer and it is more complex. During the late 1800s, adolescence was generally considered to be a shorter period of time, with many young individuals entering the workforce at an early age.
In contrast, today's society places more emphasis on education and personal development during the teenage years, resulting in a longer adolescent period. Additionally, technological advancements and the complexities of modern life contribute to the increased complexity of adolescence in the present day.