CBSE Class 12 Biology Question paper 2012 Set 03

CBSE Class 12 Biology Question paper 2012 (3). Students can download the last year question papers using the link below. Free download of examination question papers with solutions.Last 10 year question papers should be practised to get better marks in examinations.

Q1. The microscopic pollen grains of the past are obtained as fossils. Mention the characteristic of the pollen grains that makes it happen.

Q2.

Name the unlabelled areas ‘a’ and ‘b’ of the pie chart (given above) representing the global biodiversity of invertebrates shoeing their proportionate number of species of major taxa.

Q3. Some allergens trigger sneezing and wheezing in human beings. What causes this type of response by the body?

Q4. Name the group of organisms and the substrate they act on to produce biogas.

Q5. Are the thorn of Bougainvillea and tendril of Cucurbita homologous or analogous? What type of evolution has brought such a similarity in them?

Q6. Mention the two additional processing which hnRNA needs to undergo after splicing so as to become functional.

Q7. Mention the pollinating agent of an inflorescence of small dull coloured flowers with well exposed stamens and large feathery stigma.Give any one characteristic of pollen grains produced by such flowers.

Q8. Which of the following is a free living bacteria that can fix nitrogen in the soil?Spirulina, Azospirillum, Somalia.

Q9. Name the muscular and the glandular layers of human uterus.Which one of these layers undergoes cyclic changes during menstrual cycle? Name the hormone essential for the maintenance of this layer.

OR

Name the hormonal composition of the oral contraceptive used by human females.Explain how does it act as contraceptive.

Q10. Explain accelerated eutrophication. Mention any two consequences of this phenomenon. 

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