Air Book Back Answers & Guides

Unit 4 > Science > Class 6 > Samacheer Kalvi - English Medium

    Choose the correct answer

  • 1. __________ is the percentage of nitrogen in air.

    a. 78%

    b. 21%

    c. 0.03%

    d. 1%

    Correct answer:

    a. 78%

    View explanation


  • 2. Gas exchange takes place in plants using ___________.

    a. Stomata

    b. Chlorophyll

    c. Leaves

    d. Flowers

    Correct answer:

    a. Stomata

    View explanation


  • 3. The constituent of air that supports combustion is __________.

    a. Nitrogen

    b. carbon-di-oxide

    c. Oxygen

    d. water vapour

    Correct answer:

    c. Oxygen

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  • 4. Nitrogen is used in the food packaging industry because it _________.

    a. provides colour to the food

    b. provides oxygen to the food

    c. adds proteins and minerals to the food

    d. keeps the food fresh

    Correct answer:

    d. keeps the food fresh

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  • 5. _______ and ______ are the two gases, which when taken together, make up about 99 percentage of air.I.Nitrogen II. carbon-di-oxide III. Noble gases IV. Oxygen

    a. I and II

    b. I and III

    c. II and IV

    d. I and IV

    Correct answer:

    d. I and IV

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  • Fill in the blanks

  • 1. __________ is the active component of air.

    Correct answer:

    Oxygen

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  • 2. The gas given out during photosynthesis is _________.

    Correct answer:

    Oxygen

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  • 3. __________ gas is given to the patients having breathing problems.

    Correct answer:

    Oxygen

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  • 4. _______ can be seen moving in a beam of sunlight in a dark room

    Correct answer:

    Dust particles

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  • 5. ________ gas turns lime water milky.

    Correct answer:

    Carbon dioxide

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  • True or false

  • 1. Inhaled air contains a large amount of carbon-di-oxide.

    Correct answer:

    False

    Correct Statement: Inhaled air contains a large amount of oxygen.

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  • 2. Planting trees help in decreasing global warming

    Correct answer:

    True

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  • 3. The composition of air is always exactly the same.

    Correct answer:

    False

    Correct Statement: The composition of air varies from place to place

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  • 4. Whales come up to the water surface to breathe in oxygen.

    Correct answer:

    True

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  • 5. The balance of oxygen in atmosphere is maintained through photosynthesis in animals and respiration in plants.

    Correct answer:

    False

    Correct Statement: The balance of oxygen in atmosphere is maintained through photosynthesis in plants and respiration in animals.

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  • Match the following

  • 1. Moving Air

    Correct answer:

    Wind

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  • 2. Layer in which we live

    Correct answer:

    Troposphere

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  • 3. Stratosphere

    Correct answer:

    Ozone layer

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  • 4. Oxygen

    Correct answer:

    Combustion

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  • 5. carbon-di-oxide

    Correct answer:

    Photosynthesis

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  • Analogy

  • 1. Photosynthesis : _____ :: Respiration : Oxygen

    Correct answer:

    carbon dioxide

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  • 2. 78% of air : Does not support combustion :: _____ : Supports combustion

    Correct answer:

    21% of air

    View explanation