The amount of $$O_2 $$ utilised by micro organisms for decomposition

The-amount of $$O_2$$ utilised by organisms in water

The total amount of $$O_2 $$ present in water

MCQ Questions for Class 12 Medical Biology Environmental Issues Quiz 3

Increase of BOD in water leads to

0%
Increase in the dissolved O $_{2}$ concentration.
0%
Decrease in the dissolved O $_{2}$ concentration.
0%
Maintenance of dissolved O $_{2}$ concentration at the same level.
0%
No effect on dissolved O $_{2}$ concentration.

In a coal power plant, electrostatic precipitators are installed to control emission of

0%
$SO_2$
0%
$NO_2$
0%
SPM
0%
CO

Which of the following strategy is not useful for global warming?

0%
Use of fossil fuel in limit
0%
Increase in forest
0%
Increasing use of nitrogen fertilizers
0%
Use of other options in the place of CFC

Which one of the following gases can deplete ozone layer in the upper atmosphere?

0%
Ammonia
0%
Methane
0%
Carbon monoxide
0%
None of the above

Bio-indicators are used for

0%
Oxygen demand
0%
Air pollution
0%
Mineral present
0%
All of the above

The BOD of an eutrophied lake will be

0%
Higher
0%
Lower
0%
Moderate
0%
Same as any other lake

Electrostatic precipitators are extensively employed to control

0%
Water pollution
0%
Air pollution
0%
Radioactive pollution
0%
None of the above

When domestic sewage mixes with river water

0%
Small animals like rats will die after drinking river water.
0%
The increased microbial activity releases micro nutrients such as iron.
0%
The increased microbial activity uses up dissolved oxygen.
0%
The river water is still suitable for drinking as impurities are only about 0.1%.

What will be the effect of addition of organic material on water?

0%
COD remain unaffected
0%
BOD remain unaffected
0%
Increases BOD
0%
Reduces BOD

Measuring 'Biochemical Oxygen Demand' is used for

0%
Estimating the amount of organic matter in sewage water.
0%
Working out the efficiency of oil driven automobile engines.
0%
Measuring the activity of Saccharomyces cerevisiae in producing curd on a commercial scale.
0%
Working out the efficiency of R.B.Cs. about their capacity to carry oxygen.

If we remove half of the forest cover of earth, what kind of crisis will occur?

0%
Many species would become extinct.
0%
Population, pollution and ecological imbalance will rise.
0%
Energy crisis will commence.
0%
The remaining forest will cause imbalance.

If forest area is reduced to half, which one of the following will be long term effect?

0%
The natives (tribals) of that area will die on account of hunger.
0%
Cattles of that area will die due to scarcity of fodder.
0%
The diversity in germplasm will affect the crop breeding.
0%
It will be converted into large desert.

Identify the incorrect statement among the following statements on the effects of deforestation.

0%
It destroys the natural habitat of wild animals.
0%
It alters the local weather patterns.
0%
It speeds up nutrient recycling.
0%
It leads to soil erosion.

Choose the wrong pair

0%
Salvodora - Desert
0%
Cenchrus - Savanna
0%
Ables - Coniferous forest
0%
Quercus - Broad leaf forest
0%
Tectona - Temperate forest

Consider the following statements (A-D) about organic farming

(A) Utilizes genetically modified crops like Bt cotton.
(B) Uses only naturally produced inputs like compost.
(C) It does not use pesticides and urea.

(D) Produces vegetables rich in vitamins and minerals.

Which of the above statements are correct?

0%
(B) and (C) only
0%
(A) and (B) only
0%
(B), (C), and (D)
0%
(C) and (D) only

Explanation

$\textbf{Correct option: }$ A

$\textbf{Solution: }$

$\textbf{Option (A) }$

$\bullet$ Organic farming is the method of agriculture with the use of compost manure and green manure instead of chemical fertilizers.

$\bullet$ Eventually, this form of practice does not use any artificial chemical pesticides and urea.

Hence, the correct option is (A)

In recent years, there has been an increasing incidence of floods in the plains of northern India because

0%
There has been an increase in annual rainfall
0%
The rate of silting of darns has gone up
0%
There has been increased deforestation in the catchment areas
0%
Increased areas of land is being self cultivated

What is the main cause for the extinction of some species in tropical forest?

0%
Deforestation
0%
Afforestation
0%
Pollution
0%
Soil erosion

Recurrence of floods in the plains of North India is due to excessive

0%
Siltation of dams
0%
Rainfall
0%
Agriculture
0%
Deforestation in catchment area

Concentration of insecticide in the animals of a species is known as ____

0%
Eutrophication
0%
Bioconcentration
0%
Bioindicator
0%
None of the above

Limit of BOD prescribed by Central Pollution Control Board for the discharge of industrial and municipal waste waters into natural surface waters, is -

0%
< 3.0 ppm
0%
<10 ppm
0%
< 100 ppm
0%
< 30 ppm

Ozone is deadly poisonous, still it performs an essential function.

0%
True
0%
False

Explanation

Ozone molecule ( $O_3$ ) is formed by the interaction of 3 oxygen molecules.
Ozone is highly reactive and can react with air and create nitrogen dioxide, another air pollutant which are poisonous for humans.
It is also present in the stratosphere as a layer and protects living organisms by keeping UV rays from reaching the earth's surface.

Relative Biological Effectiveness (RBE) usually refers to the damages caused by

0%
High temperature
0%
Pollution
0%
Radiation
0%
Low temperature

Assertion :UV - rays are carcinogenic in nature.

Reason : UV - rays rupture DNA strands and induce mutations to cause cancers.

0%
If both assertion and reason are true and the reason is the correct explanation of the assertion.
0%
If both assertion and reason are true but reason is not the correct explanation of the assertion.
0%
If assertion is true but reason is false.
0%
If the assertion and reason both are false.
0%
If assertion is false but reason is true.

Solid waste serve as useful resource for providing energy for our industries.

0%
True
0%
False
0%
Nihter
0%
Either

Many wild animals have either become extinct or are endangered mainly due to

0%
Scarcity of food
0%
Over crowding
0%
Hunting
0%
Deforestation

Match column -I with column-II and select the correct answer using the codes given below :
Column-I Column -II
(A) Global warming (p) Eutrophication
(B) Algal bloom (q) CO, CO

$_{2}$
(C) Nitrogen fixation (r) Rhizobium
(D) Pseudomonas (s) Fossil Fuel
(E) Non-renewable resource (t) Denitrification

0%
(A)- p, (B)- q, (C)- r, (D)- t, (E)- s
0%
(A)- q, (B)- p, (C)- r, (D)- t, (E)- s
0%
(A)- q, (B)- p, (C)- r, (D)- s, (E)- s
0%
(A)- q, (B)- p, (C)- s, (D)- r, (E)- t

Explanation

Global warming is caused by greenhouse gases likeCO, CO

$_ 2$ , CFC etc. An algal bloom is the growth of algae due to nutrient enrichment in lake or eutrophication. A non-renewable resource is the resources that cannot be replaced by natural mean like coal, petroleum. Rhizobium makes a symbiotic relationship with the roots of the leguminous plant and helps plant to fix atmospheric nitrogen.

Thus, the correct answer is option B.

A successful forest conservation strategy should involve

0%
Protection of animals at the highest trophic level
0%
Protection of only sonsumers
0%
Protection of only herbivores
0%
Comprehensive programme to protect all the physical and biological components

Ozone depletion is occurring due to

0%
PCB
0%
CO
0%
PAN
0%
None of the above

Which one of the following is responsible for causing skin cancer and mutation?

0%
Ozone depletion
0%
Smog formation
0%
Snowfall
0%
Smoke from aeroplane

Explanation

Smog is an air pollutant that refers to smoky fog. It causes premature death from a respiratory disease, increases the frequency of birth defect but does not cause mutation. Effect on the health of snowfall is mainly concerned with respiratory defects due to improper ventilation.

Smoke from an airplane has higher concentrations of nitrogen dioxide (NO

$_2$ ) which leads to the global warming. It also reacts with ammonia and moisture to produce small particles that are deposited in lungs causing respiratory and lungs related disorders, and also aggravate the heart diseases.

The ozone layer is present in the atmosphere, and it prevents harmful UV radiation from entering into the Earth which has the capability to cause skin cancer, cataracts in human beings. UV is a nonionizing radiation that induces mutation by producing thymidine dimers. CFC a greenhouse gas reacts with ozone in the presence of UV radiation splits the O

$_3$ molecule into the O

$_2$ and free oxygen and leads to the ozone depletion. The depleted ozone cannot absorb UV radiation. Thus, the correct answer is option A.

Radioactive substances can cause

0%
Cancer
0%
Malaria
0%
Dysentry
0%
Common cold

The presence of ozone in the atmosphere of earth

0%
Hinders higher rate of photosynthesis
0%
Has been responsible for increasing the average global temperature in the recent past
0%
Helps in checking the ultra violet rays to earth
0%
Is advantageous, since it supplies oxygen for people travelling in jets

If the river water is polluted with domestic sewage and garbage, it leads to the depletion of

0%
CO $_2$
0%
CO
0%
O $_2$
0%
All of the above

The major pollutants to deplete ozone are

0%
Chlorofluorocarbons
0%
Nitrogen oxides
0%
Hydrocarbons
0%
All of the above

If BOD of river is high, it means that the river

0%
Is not polluted
0%
Is very polluted
0%
Does not have green plants
0%
Get least amount of light

The ozone layer 'ozonosphere' occurs in

0%
Thermosphere
0%
Troposphere
0%
Stratosphere
0%
Heterosphere

'Biological Oxygen Demand' (BOD) is a measure of

0%
Industrial wastes poured into water bodies
0%
Extent to which water is polluted with organic compounds
0%
Amount of carbon monoxide inseparably combined with haemoglobin
0%
Amount of oxygen needed by green plants during night

Measuring 'Biochemical Oxygen Demand' (BOD) is a method used for

0%
Estimating the amount of organic matter in sewage water.
0%
Measuring the activity of Saccharomyces cervisae in producing curd on a commercial scale.
0%
Working out the efficiency of RBCs, about their capacity to carry oxygen.
0%
Working out the efficiency of oil driven automobile engines.

Supersonic jets cause pollution by thinning of

0%
O $_3$ layer
0%
SO $_2$ layer
0%
O $_2$ layer
0%
CO $_2$ layer

Explanation

90% of naturally occurring atmospheric ozone occurs in the stratosphere. Stratospheric ozone is very important, it removes almost all incoming UVA, and 70% of the incoming UVB at equator, 90% at poles. All aircraft produce water, CO

$_2$ , CO etc. in exhaust gases. Most commercial flights are confined to the troposphere, but high-level supersonic aircraft inject pollutants into the stratosphere, which leads to the thinning of the ozone layer. Of these nitrogen oxides are especially harmful.

Thus, the correct answer is option A.

Catalytic converter is involved in the control of

0%
Air pollution
0%
Radioactive pollution
0%
Sewage and chemical from industry
0%
Nuclear pollution

Which one of the following is the correct percentage of the two (out of the total of 4) green house gases that contribute to the total global warming?

0%
CFCs 14%, Methane 20%
0%
CFCs 20%, Methane 14%
0%
N $_2$ O 6%, CO $_2$ 86%
0%
Methane 20%, N $_2$ O 18%

Explanation

$\textbf{Correct option:A}$

$\textbf{Solution:}$

$\bullet$ The earth's temperature rises as a result of the greenhouse effect.

$\bullet$ The gases that cause the greenhouse effect traps infrared radiation, causing the earth's surface to heat up.

$\bullet$ Water vapour, carbon dioxide, methane, nitrous oxide, and ozone are the principal greenhouse gases in the earth's atmosphere.

Composition of greenhouse gases are

$_2$ - 56%

CFCs -14%,

Methane - 20%

Nitrous Oxides - 8%,

Water Vapours - 2%.

Hence, the correct answer is option A

The reason for global warming is

0%
Long wavelength radiation are absorbed by the atmosphere
0%
Short wavelength radiation are absorbed by the atmosphere
0%
Atmosphere traps radiations to increase the temperature
0%
UV and infra red radiations

Explanation

$\textbf{Correct option:}$

$\textbf{(A)}$

$\textbf{Solution:}$

$\bullet$ The sun sends energy to the planet in the form of UV (ultraviolet), visible, and near-IR (infrared) radiation, the vast majority of which passes through the atmosphere unabsorbed.

$\bullet$ About half of the total energy available at the top of the atmosphere is absorbed at the earth's surface.

$\bullet$ The surface radiates far IR thermal radiation, which has wavelengths that are primarily considerably longer than the wavelengths that were absorbed, because it is warm.

$\bullet$ The atmosphere absorbs the majority of this heat radiation, which is re-emitted both above and downwards; that which is radiated downwards is absorbed by the earth's surface.

$\bullet$ The atmosphere traps long-wavelength thermal radiation, resulting in a higher temperature than if it were not present.

$\bullet$ The increase in greenhouse gas levels has resulted in significant heating of the world, resulting in global warming.

$\textbf{Thus the Correct option is (A)}$

Global warming can be controlled by

0%
Reducing reforestation, increasing the use of fossil fuel
0%
Increasing deforestation, slowing down the growth of human population
0%
Increasing deforestation, reducing efficiency of energy usage
0%
Reducing deforestation, cutting down use of fossil fuel

Explanation

Global warming is the biggest challenge for the developing countries like India. The rapid increase in human population and the increased levels of pollution are the major contributors of global warming.
The percentage of heat-trapping carbon dioxide (CO $_2$ ) increases due to the burning of fossil fuels to generate electricity, fuel our cars, and heat our homes.
Deforestation also increases the concentration of carbon dioxide in the atmosphere.

So, the correct answer is option D.

The worst enemy of ozone is

0%
Liquid NH $_3$
0%
SO $_2$
0%
CH $_4$
0%
CFCs

Which method is most effective in controlling floods?

0%
Digging deep canals
0%
Reforestation
0%
Deforestation
0%
Constructing dams

Ozone layer of upper atmosphere is being destroyed by

0%
Sulphurdioxide
0%
Carbondioxide
0%
Chlorofluorocarbon
0%
Smog

BOD is

0%
The-amount of $O_2$ utilised by organisms in water
0%
The amount of $O_2$ utilised by micro organisms for decomposition
0%
The total amount of $O_2$ present in water
0%
All of the above

The major source of BOD in the river Ganga is

0%
Leaf litter
0%
Fishes
0%
Human waste
0%
Aquatic plants

Explanation

The Ganges river basin is one of the most fertile and densely populated regions in the world that covers an area of 1,80,000

$km^2$ . The river flows through 29 cities with population over 100,000; 23 cities with population between 50,000 and 100,000, and about 48 towns.

A large proportion of the waste in the Ganges is from this population through domestic usage like bathing, laundry and public defecation. An analysis of the Ganges water in 2006 showed significant associations between waterborne or enteric disease due to the use of the river for bathing, laundry, washing, eating, cleaning utensils, and brushing teeth.

Increase in BOD of water reservoir is due to

0%
Algae
0%
Soil
0%
Moss
0%
Waste product

'Biological Oxygen Demand' (BOD) is a measure of

0%
Industrial wastes poured into water bodies.
0%
Extent to which water is polluted with organic compounds.
0%
Amount of carbon monooxide inseparably combined with haemoglobin.
0%
Amount of oxygen needed by green plants during night.

Which of the following is a correct statement?

0%
Biogas contains 55% of nitrogen.
0%
Producer gas contains 33% of carbon monoxide.
0%
CO $_2$ is the major constituent in biogas and producer gas.
0%
None of the above.

Explanation

$\textbf{Correct option:}$

$\textbf{(D)}$

$\textbf{Solution:}$

$\textbf{Explanation for Incorrect statements}$

$\textbf{Option (A)}$

$\bullet$ Biogas is primarily made up of methane (the fuel's energy source) and carbon dioxide.

$\bullet$ Small amounts of nitrogen or hydrogen may also be present.

$\bullet$ Sulphur or siloxanes can be contaminants in biogas, however this depends on the digester input.

$\textbf{Option (B)}$

$\bullet$ A flammable mixture of nitrogen, carbon monoxide, and hydrogen produced in a furnace by passing air with steam over burning coke or coal.

$\bullet$ Nitogen oxide = 55%, CO = 29%, Carbon dioxide = 5.5%, and Hydrogen = 10.5% are the average production gas compositions in volume.

$\textbf{Option (C)}$

$\bullet$ Methane (55-70%), Carbon dioxide (30-45%), and traces of gases like Hydrogen sulphide and ammonia make up the majority of biogas.

$\bullet$ Methane will be the primary component.

$\textbf{Thus the Correct option is (D)}$

CBSE Questions for Class 12 Medical Biology Environmental Issues Quiz 3 - MCQExams.com

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Practice Class 12 Medical Biology Quiz Questions and Answers

CBSE Questions for Class 12 Medical Biology Environmental Issues Quiz 3 - MCQExams.com

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Practice Class 12 Medical Biology Quiz Questions and Answers

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