Choose the correct option: (i) Sometimes, manure is added to the soil before tilling because -
A)
less manure is used.
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B)
it helps in proper mixing of manure with soil.
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C)
it saves labour and time.
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D)
none of the above.
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Choose the correct option: (ii) The most common carrier of communicable disease is :
A)
Ant
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B)
Housefly
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C)
Dragonfly
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D)
Spider
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Choose the correct option: (iii) The bread or idli dough rises because of
A)
heat
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B)
grinding
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C)
growth of yeast cells
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D)
kneading
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Choose the correct option: (iv) Nitrogen fixation is brought about by
A)
(a) blue-green algae
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B)
(b) bacteria
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C)
(c) both (a) and (b)
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D)
(d) none of these
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Choose the correct option: (v) The strongest fibre is called
A)
rayon
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B)
nylon
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C)
acrylic
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D)
none of these
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Choose the correct option: (vi) Which of the following statements is correct?
A)
All metals are ductile.
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B)
All non-metals are ductile.
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C)
Generally, metals are ductile.
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D)
All are true.
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Choose the correct option: (vii) Fossil fuels are obtained from:
A)
Remains of non-living materials.
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B)
Dead remains of birds only.
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C)
Dead remains of insects only.
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D)
Dead remains of living organisms.
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Choose the correct option: (viii) The calorific value of a fuel is expressed in a unit called
A)
kilojoule per litre
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B)
kilogram per milliliter
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C)
kilojoule per gram
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D)
kilojoule per kilogram
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Choose the correct option: (ix) Which one of the following changes may occur due to desertification?
A)
Decreases in atmospheric temperature.
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B)
Increase in water holding capacity of soil.
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C)
Increased chance of floods.
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D)
Conversions of fertile land into a desert.
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Choose the correct option: (x) The unit of measurement used for expressing dimension (size) of cells is:
A)
Centimeter
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B)
micrometer
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C)
Millimeter
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D)
metre
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(i) What is static electricity?
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(ii) Name the substance which does not burn with flame.
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(iii) At what angles are mirrors inclined in a kaleidoscope and a periscope respectively?
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(iv) Reproduction in which single parent is Required
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(v) Which micro-organism is responsible for causing Rust of Wheat?
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(vi) Name two water pollutants which are toxic for both plants and animals.
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What is the difference between stars and planets?
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Look at fig. below. Can the image of the child in it be obtained on the screen?
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The aluminum strips on an electroscope are replaced by plastic strips and a charged body is brought in contact with the metal clip. What will happen?
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A pendulum oscillates 40 times in 4 seconds. Find its time period and frequency.
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Two boys are riding their bicycle on the same concrete road. One has new tyres on his bicycle while the other has tyres that are old and used. Which of them is more likely to slip while moving through a patch of the road which has lubricating oil spilled over it?
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Two persons are applying forces on two opposite sides of a moving cart. The cart still moves with the same speed in the same direction. What do you infer about the magnitudes and direction of the forces applied.
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Fill in the blank circles in figure and identify the sex of child A and B.
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Why is acrylic more popular than natural woollen fibres?
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Classify the following crops into Kharif and Rabi crop and write in the tabular columns given below: Maize, paddy, mustard, pea, gram, wheat, groundnut, cotton.
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Some natural resources are given below. Classify them into the exhaustible and inexhaustible natural resources. Air, coal, natural gas, sunlight, petroleum, minerals, forests, oxygen.
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How are acids and bases formed?
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(i) Differentiate between eukaryotes and prokaryotes on the basis of nucleus. (ii) Give at least 2-2 examples each of eukaryotic and prokaryotic cells.
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In Delhi, due to bad quality of air, people felt difficulty in breathing and irritation in eyes. (i) What was the reason of bad condition of air? (ii) Name the pollutant present in air and other things creating this condition,
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Identify the metals and non-metals which are (i) used in making utensils and machinery parts (ii) essential for our life, which all living being inhale during respiration (iii) used in thermometers, present in liquid state.
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Although wood has a very high calorific value, we still discourage its use as a fuel. Explain.
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Why pituitary gland is called 'Master Gland'?
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Fig. shows a car sticking to an electromagnet. Name the forces acting on the car. Which one of them is larger?
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After observing answer the following. (i) Read the following statements and label them in the figure: (a) The part which produces female gametes. (b) The part where development of the baby takes place. (c) The part through which the developing embryo passes to reach the uterus. (ii) Explain the future development of the embryo that would take place after it gets embedded in the uterus.
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(i) Draw a well labelled diagram to show the internal structure of Human Eye. (ii) Write the function of Iris and Retina. (iii) How will you take proper care of your eyes? Write any two.
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(i) What are audible and inaudible sounds? Write the range of audible frequency for human ear. (ii) Explain in what way noise pollution is harmful for humans.
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Explain the mechanism of thunderstorms or story of lightning.
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