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 QuestionsLong Answer Type

31.

(a) Write the specific location and the functions of the following cells in human males:

(i) Leydig cells

(ii) Sertoli cells

(iii) Primary spermatocyte

(b) Explain the role of any two accessory glands in human male reproductive system.

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32. Explain the salient features of Hugo de Vries theory of mutation. How is Darwin theory of natural selection different from it? Explain.
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33.

(a) Name the primates that lived about 15 million years ago. List their characteristic features.

(b) (i) Where was the first man-like animal found?

(ii) Write the order in which Neanderthals, Homo habilis and Homo erectusappeared on earth.

State the brain capacity of each one of them.

(iii) When did modern Homo sapiens appear on this planet?


(a) Dryopithecus (ape-like) and Ramapithecus (man-like) were the two primates that lived 15 million years ago. These primates were hairy and their walk was similar to that of chimpanzees.

(b) (i) The first man-like animal was found in Africa.

(ii) 

Year

Evolution

Brain capacity

2 million years ago

Homo habilis (Australopithecines) lived in East Africa

650- 800 cc

1.5 million years ago

Homo erectus

900 cc

1,000 - 40,000 years ago

Neanderthal man

1400 cc


(iii) Modern Homo sapiens first appeared primarily in east Africa about 75,000 to 10,000 years ago.
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34.

(a) Explain primary productivity and the factors that influence it.

(b) Describe how do oxygen and chemical composition of detritus control decomposition?

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35.

(a) What is El Nino effect? Explain how it accounts for biodiversity loss.

(b) Explain any three measures that you as an individual would take, to reduce environmental pollution.

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