Assertion (A): Menstrual cycle starts only after attaining sexual maturation (puberty).
Reason (R): The first menstruation begins at puberty and is called menopause.
Answer & explanation
Correct answer: option 4
The correct answer is Option (4) → Assertion is true but the reason is false.
The menstrual cycle is the reproductive cycle of female primates. It begins at puberty and repeats about every 28/29 days. Two words mark its two ends: menarche is the first menstruation, at puberty, and menopause is when the cycles stop, at about 50 years of age.
Assertion (A): Menstrual cycle starts only after attaining sexual maturation (puberty). — True. Menstrual cycles start only when the girl reaches sexual maturity. The first menstruation comes at puberty.
Reason (R): The first menstruation begins at puberty and is called menopause. — False. The first menstruation at puberty is called menarche, not menopause. Menopause is the stopping of menstrual cycles at around 50 years of age.
NCERT Extract:
Menstrual Cycle – “The reproductive cycle in the female primates (e.g. monkeys, apes and human beings) is called menstrual cycle. The first menstruation begins at puberty and is called menarche. In human females, menstruation is repeated at an average interval of about 28/29 days, and the cycle of events starting from one menstruation till the next one is called the menstrual cycle.”
Menstrual Cycle – “… In human beings, menstrual cycles ceases around 50 years of age; that is termed as menopause. Cyclic menstruation is an indicator of normal reproductive phase and extends between menarche and menopause.”