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प्रश्न
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उत्तर
Carbon dioxide is removed from the atmosphere by:
(i) Producers - Producers or green plants use carbon dioxide through photosynthesis. A small amount of carbon dioxide is used by chemosynthetic bacteria also.
(ii) Marine Organisms - Some amount of carbon dioxide is directly fixed by a few marine organisms and sea water absorbs carbon dioxide in the form of dissolved carbon dioxide, carbonic acid, carbonate and bicarbonates.
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संबंधित प्रश्न
An experiment was set up as shown in the figure given below . The twig in the diagram was intact on the plant and it was as such in sunlight for a few hours .

(i) What is the aim of the above experiment ?
(ii) Why was potassium hydroxide placed inside the conical flask ?
(iii) What test would you perform on the leaf inside the flask?
(iv) What is the expected result of the above test ?
(v) Is it necessary to similarly test on outer leaf also ? Giva a reason .
Two healthy green plants were placed in the dark for 24 hours. They were then set up, as shown in the figure, for 4 hours. Then a leaf was taken from each plant and
the chlorophyll was removed from the leaves:
( i) What is the next and final step in this experiment?
( ii ) What would be the results of the final step?
( iii ) Why was it necessary to grease the glass sheet?
( iv ) What hypothesis is being tested in this experiment?

Complete the following statement by choosing the correct alternative given below :
All animals would die on the earth if there was no ______.
The diagram is set up to demonstrate an experiment. Pond weed was placed in five water-filled tubes. The experiment was set up as shown in the diagram. The tubes were then left for 24 hours. Write the correct answer out of the five available choices:
(i) In which tube would you except to find the plant with the least amount of starch?
(a ) 1 (b) 2 (c) 3 (d) 4 (e ) 5
(ii) The tube in which most oxygen would be found is
(a ) 1 (b) 2 (c) 3 (d) 4 (e ) 5
(iii) The tube in which least carbon dioxide would be found is
(a ) 1 (b) 2 (c) 3 (d) 4 (e ) 5
(iv) The tube in which the plant would survive for the shortest length of time is
(a ) 1 (b) 2 (c) 3 (d) 4 (e) 5

Why is it not possible to demonstrate respiration in a green plant kept in sunlight?
Photosynthesis in green plants is directly and indirectly dependent on so many plant structures.
Explain briefly the role of the following structures in this process Guard cells.
Given below is the representation of a certain phenomenon in nature. With four organisms 1-4.

Name any one organism that could be shown at No .5
The diagram below shows two test-tubes A and B. Test-tube A contains a green water plant. Test-tube B contains both a green water plant and a snail. Both test-tubes are kept in sunlight. Answer the questions that follow:

(a) Name the physiological process that releases the bubbles of oxygen.
(b) Explain the physiological process as mentioned above in (a).
(c) What is the purpose of keeping a snail in test-tube B?
(d) Why does test-tube B have more bubbles of oxygen?
(e) Give an example of a water plant that can be used in the above experiment.
(f) Write the overall chemical equation for the above process.
Differentiate Between:
Light reaction and Dark reaction.
