Final answer:
Mammals advertise sexual maturity through physical traits, hormonal cycles, and courtship behaviors.
Step-by-step explanation:
Mammals advertise sexual maturity through various means of communication and display. Some mammals, like marsupials, have physical traits that indicate sexual maturity, such as pouches where young are carried. Others, like elk and lions, exhibit sexual dimorphism, where males have certain physical characteristics like antlers or a mane that distinguish them from females. In many mammals, including humans, females go through hormonal cycles that make them sexually attractive and receptive to males during certain periods. Courtship behaviors, such as vocalizations, dances, and displays, are also common in mammals.