Final answer:
The claim that females can have their first estrous cycle as early as 4 months is false for humans but may be true for certain other species. In human females, puberty begins around 9-10 years of age, with menarche typically occurring at about 12.5 years.
Step-by-step explanation:
The statement 'Females can have their first estrous cycle as early as 4 months' is generally false when referring to human females; however, it might be true for certain other mammal species. For example, domestic cats and dogs can experience their first estrous cycle at an earlier age, sometimes as early as 4 to 6 months. It's important to distinguish between different species when discussing reproductive cycles.
Human females typically begin puberty between the ages of nine and ten with menarche, the beginning of menstruation, occurring on average at around 12.5 years of age. This onset of menstruation signifies the start of reproductive capability and is a key milestone in the female reproductive cycle.
The two major events that mark the beginning and end of the reproductive period in females are menarche and menopause. Menarche typically occurs around age 12.5 years, while menopause usually happens in a woman's late 40s to early 50s.