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Published on: 25/05/2021
QB365 Provides the updated NCERT Examplar Questions for Class 12 Biology, and also provide the detail solution for each and every ncert examplar questions , QB365 will give all kind of study materials will help to get more marks
Download CBSE Class 12th Standard CBSE Biology question papers, sample papers, important questions, and previous year solved papers in PDF format. Get free study materials, NCERT solutions, and exam preparation resources for Class 12th Standard CBSE Biology
Questions + Answers key
Take MCQ Biology Test1.
Match the items column I and column II and choose the correct option:
| Column I | Column II |
| (a) UV | (i) Biomagnification |
| (b) Biodegradable Organic mater | (ii) Eutrophication |
| (c) DDT | (iii) Snow blindness |
| (d) Phosphates | (iv) BOD |
| A | B | C | D |
| ii | i | iv | iii |
| A | B | C | D |
| iii | ii | iv | i |
| A | B | C | D |
| iii | iv | i | ii |
| A | B | C | D |
| iii | i | iv | i |
2.
Algal blooms impart a distinct colour to water due to:
their pigments
excretion of coloured substances
formation of coloured chemicals in water facilitated by physiological degradation of algae.
absorption of light by algal cell wall.
3.
Why is it necessary to remove sulphur from petroleum products?
To reduce the emission of sulphur dioxide in exhaust fumes
To increase efficiency of automobiles engines
To use sulphur removed from petroleum for commercial purposes
To increase the life span of engine silencers
4.
Catalytic converters are fitted into automobiles to reduce emission of harmful gases. Catalytic converters change unburnt hydrocarbons into:
carbon dioxide and water
carbon monoxide
methane
carbon dioxide and methene
5.
Increase in BOD in water leads to
increase in the disolved O2 conc.
decrease in the dissolved O2 conc.
maintenance of disolved O2 conc. at the same level
no effect on dissolved O2 conc.
6.
A lake near a village suffered heavy mortality of fishes within a few days. Consider the following reasons for this.
(a) lots of urea and phosphate fertilizers were used in the crops in the vicinity
(b) the area was sprayed with DDT by an aircraft
(c) the lake water turned green and stinky
(d) phytoplankton populations in the lake declined initially thereby greatly reducing photosynthesis
Which two of the above were main reasons of fish mortality in the lake?
A, C
A, B
B, C
C, D
7.
A genetically engineered microorganism used successfully in bioremediation of oil spills is a species of
Trichoderma
Xanthomonas
Bacillus
Pseudomonas
8.
In a coal fired power plant electrostatic precipitators are installed to control emission of
NOX
SPM
CO
SO2
9.
Common indicator organism of water pollution is
Eichhornia crassipes
Escherchia coli
Entamoeba histolytica
Lemna pancicostata
10.
In 1984, the Bhopal gas tragedy took place because methyl isocyanate
Reacted with ammonia
Reacted with CO2
Reacted with water
Reacted with DDT
1.
(c)
| A | B | C | D |
| iii | iv | i | ii |
2.
(a)
their pigments
3.
(a)
To reduce the emission of sulphur dioxide in exhaust fumes
4.
(a)
carbon dioxide and water
5.
(b)
decrease in the dissolved O2 conc.
6.
(b)
A, B
7.
(d)
Pseudomonas
8.
(b)
SPM
9.
(b)
Escherchia coli
10.
(c)
Reacted with water
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