Study the graph given below. Explain how oxygen concentration is

Subject

Biology

Class

CBSE Class 12

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Sample Papers

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 Multiple Choice QuestionsShort Answer Type

11.

Differentiate between albuminous and non-albuminous seeds, giving one example of each.

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12. Explain the process of RNA interference.
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13. List the key tools used in recombinant DNA technology.
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14. Name the two types of immune systems in a human body. Why are cell-mediated and humoral immunities so called?
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15.

Write the scientific names of the causal organisms of elephantiasis and ringworm in humans. Mention the body parts affected by them.

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16. Justify with the help of an example where a deliberate attempt by humans has led to the extinction of a particular species.
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17. Identify A, D, E and F in the diagram of an antibody molecule given below.

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18.

Study the graph given below. Explain how oxygen concentration is affected in the river when sewage is discharged into it.


The introduction of sewage caused a sudden and sharp drop in the amount of dissolved oxygen in the river. This is caused due to an increase in the biological oxygen demand (BOD). This in turn leads to the death of fishes and other aquatic life. As the sewage gets diluted due the flow of the water, the river slowly regains some of its oxygen concentration.

 

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19. Explain how a hereditary disease can be corrected. Give an example of first successful attempt made towards correction of such diseases.
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20. Draw a diagram of a male gametophyte of an angiosperm. Label any four parts. Why sporopollenin is considered the most resistant organic material?
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