Subject

Biology

Class

CBSE Class 12

Pre Boards

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Sample Papers

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 Multiple Choice QuestionsShort Answer Type

11.

Identify'A' , 'B', 'C' and 'D' in the given table

Crop Variety Resistance to disease
A Himgiri Leaf rust
Cauliflower Pusa Shubhra B
Brassica Pusa Swarnim C
Cowpea D Bacterial blight
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12.

Why is breast-feeding recommended during the initial period od an infant's growth? Give reasons. 

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13.

Give an example of an autosomal recessive trait in humans. Explain its pattern of inheritance with the help of a cross. 


Sickle Cell Anaemia is an autosomal recessive trait in humans. The genes responsible for this disease are located in autosomes. The disease being recessive the trait should be present in homozygous condition, for it to express.
People who carry a single copy of the gene are clinically normal but are carriers of the disease and can pass on the defective gene to their subsequent generation.

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14. Describe the experiment that helped Louis Pasteur to dismiss the theory of spontaneous generation of life.
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15.

Plant breeding technique has helped sugar industry in North India. Explain how.

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16.

Suggest and describe a technique to obtain multiple copies of a gene of interest in vitro.

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17.

What is a GMO? List any five possible advantages of a GMO is a farmer. 

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18.

During a school trip to 'Rohtang pass' one of your classmate suddenly developed 'Altitude sickness'. But, she recovered after sometime.

(a) Mention one symptom to diagnose the sickness.
(b) What causes the sickness?
(c) How could she recover by herself after sometime?

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19.

How has RNAi technique helped to prevent the infestation of roots in tobacco plants by a nematode Meloidegyne incognita?

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20.

In in a food-chain, a trophic level represents a functional level, not a species. Explain.

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