Which of the following events marks the beginning of the menstrual cycle in human females?
Shedding of the uterine lining
The menstrual cycle (about 28 days) is counted from day 1 of menstruation.
If the egg is not fertilised, the thickened uterine lining (endometrium) breaks down and is shed with blood — this menstrual flow starts the cycle.
Ovulation occurs around the middle of the cycle (about day 14); fertilisation and implantation happen only if pregnancy begins.
Hence, the shedding of the uterine lining marks the beginning of the menstrual cycle.
Similar Questions
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Which of the following options explains why menstruation does not occur if fertilization takes place during the menstrual cycle?
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Important Questions from Reproduction
Cells of the tapetum possess dense cytoplasm and generally have ________.
Human chorionic gonadotropin:
Zygotes do not undergo reduction division immediately. They produce a multicellular body called a -
Which of the following organisms does NOT show asexual reproduction by means of fission?
The pollen needs to be transferred from the stamen to the stigma. If this transfer of pollen occurs in the same flower, it is referred to as __________ . On the other hand, if the pollen is transferred from one flower to another, it is known as ______
