Subject

Biology

Class

CBSE Class 12

Pre Boards

Practice to excel and get familiar with the paper pattern and the type of questions. Check you answers with answer keys provided.

Sample Papers

Download the PDF Sample Papers Free for off line practice and view the Solutions online.
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 Multiple Choice QuestionsShort Answer Type

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1.

How many chromosomes do drones of honeybee possess? Name the type of cell division involved in the production of sperms by them.

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2.

What is a cistron?

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3. Retroviruses have no DNA. However, the DNA of the infected host cell does possess viral DNA. How is it possible?
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4. Why do children cured by enzyme-replacement therapy for adenosine deaminase deficiency need periodic treatment?
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5. List two advantages of the use of unleaded petrol in automobiles as fuel.
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6.

Why do moss plants produce very large number of male gametes? Provide one reason. What are these gametes called?

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7.

(a) Select the homologous structures from the combinations given below :
(i) Forelimbs of whales and bats
(ii) Tuber of potato and sweet potato
(iii) Eyes of octopus and mammals
(iv) Thorns of Bougainvillea and tendrils of Cucurbita

(b) State the kind of evolution they represent.

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8.

(a) Why are the plants raised through micro-propagation termed as somaclones?
(b) Mention two advantages of this technique.

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9.

Explain the different steps involved during primary treatment phase of sewage.

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10. What is mutualism? Mention any two examples where the organisms involved are commercially exploited in agriculture.
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