What is menstruation? Explain.
At puberty, in girls the ovaries get enlarged and starts producing eggs (ovum). One egg matures and is released by one of the ovaries at a time or we can say once in about 28 to 30 days. During this period, the wall of the uterus become thick so as to receive the egg. If the egg is fertilized then it begins to develop and results in pregnancy and if this egg is not fertilized then the released egg and thickened lining of the uterus along with its blood vessels are shed off causing bleeding in female which is known as menstruation.
Popular Questions of Class 8 Science
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Describe with the help of a diagram an instrument which can be used to detect a charged body.
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Sketch larynx and explain its function in your own words.
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What is metamorphosis? Give examples.
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Make a labelled diagram of a candle flame.
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The following Table shows the total power shortage in India from 1991– 1997. Show the data in the form of a graph. Plot shortage percentage for the years on the Y-axis and the year on the X-axis.
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Arrange the following boxes in proper order to make a flow chart of sugarcane crop production.
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Make sketches of animal and plant cells. State three differences between them.
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Describe the construction of a kaleidoscope.
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Make a sketch of the human nerve cell. What function do nerve cells perform?
Recently Viewed Questions of Class 8 Science
- Q:-
Match items in column A with those in column B.
A B
(i) Kharif crops (a) Food for cattle
(ii) Rabi crops (b) Urea and super phosphate
(iii) Chemical fertilisers (c) Animal excreta, cow dung urine and plant waste
(iv) Organic manure (d) Wheat, gram, pea
(e) Paddy and maize - Q:-
How many images of a candle will be formed if it is placed between two parallel plane mirrors separated by 40 cm?
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Make sketches of animal and plant cells. State three differences between them.
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Explain why objects moving in fluids must have special shapes.
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Write short notes on the following:
(a) Cytoplasm
(b) Nucleus of a cell - Q:-
Explain how CO2 is able to control fires.
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Indicate whether the following statements are True (T) or False (F).
(a) Unicellular organisms have one-celled body. (T/F)
(b) Muscle cells are branched. (T/F)
(c) The basic living unit of an organism is an organ. (T/F)
(d) Amoeba has irregular shape. (T/F) - Q:-
The process that you saw in Activity 14.7 is used for purification of copper. A thin plate of pure copper and a thick rod of impure copper are used as electrodes. Copper from impure rod is sought to be transfered to the thin copper plate. Which electrode should be attached to the positive terminal of battery and why?
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The table below shows the data on likely heights of boys and girls as they grow in age. Draw graphs showing height and age for both boys and girls on the same graph paper. What conclusions can be drawn from these graphs?
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Fill in the blanks with suitable words.
(a) Time taken by an object to complete one oscillation is called ................... .
(b) Loudness is determined by the .........................of vibration.
(c) The unit of frequency is..........................
(d) Unwanted sound is called ......................... .
(e) Shrillness of a sound is determined by the ................. of vibration.
- NCERT Chapter