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

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 Multiple Choice QuestionsShort Answer Type

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31.

In which phase of the cell cycle does replication occur in Eukaryotes? What would happen if cell-division is not followed after DNA replication?


DNA replication occurs in S phase of cell cycle in eukaryotes. If cell division is not followed after DNA replication then the replicated chromosomes (DNA) would not be distributed to daughter nuclei. A repeated replication of DNA without any cell division results in the accumulation of DNA inside the cell. This would increase the volume of the cell nucleus, thereby causing cell expansion.

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32.

Explain Darwinian theory of evolution with the help of one suitable example. State the two key concept of the theory.

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33.

Study the graph given below and answer the questions that follow:


(i) Write the status of food and space in the curves (a) and (b).


(ii) In the absence of predators, which one of the two curves would appropriately depict the prey population?

(iii) Time has been shown on X-axis and there is a parallel dotted line above it. Give the significance of this dotted line.

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34.

What is primary productivity? Why does it vary in different types of ecosystems?

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35.

State the relation between gross and net primary productivity.

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36.

Coconut palm is monoecious, while date palm is dioecious. Why are they so called?

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37.

Draw a sectional view of human ovary and label the different follicular stages, ovum and Corpus luteum.

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38.

How is 'oogenesis' markedly different from 'spermatogenesis' with respect to the growth till puberty in the humans?

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39.

Draw a sectional view of human ovary and label the different follicular stages, ovum and Corpus luteum.

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40.

Mention any three characteristics of Neanderthal man that lived in near east and central Asia.

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