Which of the following options explains why menstruation does not occur if fertilization takes place during the menstrual cycle?
The lining of the uterus is kept intact to support the developing embryo.
In every menstrual cycle the inner lining of the uterus (endometrium) becomes thick and rich in blood vessels to receive a fertilised egg. If the egg is not fertilised, this lining breaks down and is shed through the vagina as menstruation.
If fertilisation takes place, the zygote develops into an embryo that gets implanted in the uterine wall. Hormones (progesterone from the corpus luteum, kept active by signals from the embryo) maintain the thick lining, so it is not shed and menstruation stops; the lining nourishes and supports the developing embryo.
Shedding of the lining is menstruation itself, so it cannot explain its absence. The ovary only pauses ovulation during pregnancy and resumes it later; it does not stop permanently. The placenta is a separate structure formed from embryonic tissue and the uterine wall, while the uterus remains as the organ that holds the foetus.
Hence, The lining of the uterus is kept intact to support the developing embryo.
Similar Questions
Which of the following explains why offsprings produced through sexual reproduction in animals are usually not identical to their parents?
Which of the following describes the function of the scrotum that houses the testes?
Which of the following conditions would prevent seed formation in a flowering plant even after pollination has occurred?
Which of the following is the main function of the vas deferens in the male reproductive system?
Which of the following structures is directly involved in the process of menstruation?
Which of the following events marks the beginning of the menstrual cycle in human females?
Where does the developing embryo in most mammals receive its nourishment?
Which of the following is NOT a function of the male reproductive system?
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Which of the following explains the importance of meiosis for maintaining chromosome number across generations?
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 ______
