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प्रश्न
Give scientific reason.
Older women are more likely to give birth to children with some abnormalities.
उत्तर
- A female has millions of oocytes at the time of birth and new ova are not formed thereafter.
- Menopause occurs at approximately 40-50 years of age and hence fewer numbers of eggs are present with reduced fertility since the oocytes have aged.
- Their ability to divide diminishes and they may not be able to complete meiotic division properly.
- Fertilization of such oocytes may result in the production of genetic abnormalities (like Down syndrome) in offspring.
Hence, older women are more likely to give birth to children with some abnormalities.
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संबंधित प्रश्न
Fill in the blank.
Implantation of embryo occurs in ------
Body breaks up into several fragments and each fragment starts to live as a new individual. This is ______ type of reproduction.
At the time of birth, there are _______________ oocytes in the ovary of a female foetus.
In meiosis, the number of chromosomes becomes ___________.
The process which the sperm undergoes before penetrating the ovum is ____________.
Mention the differences between spermiogenesis and spermatogenesis.
At what stage of development are the gametes formed in newborn male and female?
Describe the structure of the human ovum with a neat labelled diagram.
The following is the illustration of the sequence of ovarian events (a-i) in a human female.
Identify the figure that illustrates ovulation and mention the stage of oogenesis it represents.
The part labelled as ______ contains the energy source that facilitates sperm motility.
Identify the longest period of menstrual cycle.
Which of the following is diploid?
Acrosome reaction in sperm is triggered by ______.
Which of the following contains a fluid filled cavity called antrum?
1st polar body is formed at which stage of oogenesis?
Which of the following is a primary sex organ of female?
Observe the given figure and answer the questions that follow.
- Label A and B.
- Identify the process.
- What happens during the process and what is formed?
What is spermatogenesis?
