Read the passage and answer the following questions:
The major events of the cycle starts with the menstrual phase, when menstrual flow occurs and it lasts for 3-5 days. The menstrual flow results due to breakdown of endometrial lining of the uterus and its blood vessels which forms liquid that comes out through vagina. Menstruation only occurs if the released ovum is not fertilised. Lack of menstruation may be indicative of pregnancy. However, it may also be caused due to some other underlying causes like stress, poor health etc. The menstrual phase is followed by the follicular phase. During this phase, the primary follicles in the ovary grow to become a fully mature Graafian follicle and simultaneously the endometrium of uterus regenerates through proliferation. These changes in the ovary and the uterus are induced by changes in the levels of pituitary and ovarian hormones.
At what average interval is menstruation repeated in human females?
Answer & explanation
Correct answer: option 1
The correct answer is Option (1) → 28/29 days.
In human females, menstruation is repeated at an average interval of about 28/29 days. The events from one menstruation till the next make one menstrual cycle, and ovulation takes place in the middle of the cycle, at about the 14th day.
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.”