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CBSE Questions for Class 9 Biology Natural Resources Quiz 9 - MCQExams.com
CBSE
Class 9 Biology
Natural Resources
Quiz 9
Low visibility in cold weather is due to which of the following pollutant/s?
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Sulfur oxides
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Nitrogen oxides
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Unburnt carbon particles
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All of the above
Explanation
The combustion of fossil fuels increases the amount of suspended particles in the air. These suspended particles could be unburnt carbon particles or substances called hydrocarbons. The presence of high levels of all these pollutants lowers visibility, especially during cold weather when moisture condenses out of the air. This is known as smog and is a visible indication of air pollution.
So, the correct answer is option C.
Sea water is saltier than rain water because
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the air around sea is saltish
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Rivers wash away salts from the earth and pour them into sea
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Sea beds have salt producing mines
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Sea animals are salt producing
State whether these sentences are true (T) or false (F).
Carbon dioxide is an important constituents of air.
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True
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False
Explanation
Air is a mixture of gases- oxygen, nitrogen, hydrogen, carbon dioxide, etc.
Carbon dioxide is a colorless and non-flammable gas at normal temperature and pressure.
Carbon dioxide is produced by the combustion of fuels, forest fires and is also released during respiration.
A molecule of carbon dioxide ($$CO_2$$) is made up of one carbon atom and two oxygen atoms.
So, the correct answer is option A.
What will be the effect of an ozone hole?
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Greenhouse effect
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Global warning
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Acid rain
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Harmful UV rays will reach the Earth's surface, causing damage to the living organisms.
Explanation
A layer of ozone around the Earth's atmosphere absorbs the harmful UV rays coming from the sun.
If there is an ozone hole or the density of ozone is less in one area, the harmful UV rays will enter the Earth's atmosphere and cause damage to living organisms. For example, exposure to harmful UV rays can cause cancer in humans.
If there were no atmosphere around the earth, the temperature of the earth will ________.
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Increase
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Go on decreasing
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Increase during day and decrease during night
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Be unaffected
Explanation
If there were no atmosphere around the earth, the temperature of the earth will increase during day and decrease during night. In the absence of atmosphere around the earth, it will be like a moon. There would be no life, no winds, no rains, no fires, no protection against harmful solar radiations. Due to absence of atmosphere around the moon, the temperature ranges from -190$$^0$$C to 110$$^0$$C. Air is a bad conductor of heat. The atmosphere has an average temperature of the earth almost steady during the day and night. It prevents sudden increase in temperature during the day time. Also, it decreases the rate of escape of heat during night time.
Thus, the correct answer is 'Increase during day and decrease during night.'
Minerals and metal are:
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Biodegradable resources
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Renewable
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Non-renewable
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Renewable and non-renewable resources
Explanation
Biodegradable resources are the ones that can be broken down into simpler substances by the action of microbes.
Renewable resources are the ones that can be replenished in nature over a period of time.
Non renewable resources are the ones that can not be replenished in nature over a period of time or they may be replenished but over a very longer period of time.
Minerals are considered to be renewable resources whereas metals are considered to be non-renewable resources.
So, the correct answer is '
Renewable and non-renewable resources'.
Which gas is likely to be reduced in the atmosphere by deforestation?
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Carbon dioxide
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Nitrogen
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Oxygen
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Sulphur dioxide
Explanation
Photosynthesis is the main process by which oxygen is recovered in the atmosphere. If there is a reduction in plants by deforestation (clearing of forests), the levels of oxygen will deplete.
Therefore, the correct answer is option C.
All forms of water that comes down on the earth, including rain, snow, hail, etc. is known as ____________.
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Evaporation
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Condensation
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Precipitation
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Accumulation
Explanation
When the condensed water particles in the atmosphere combine with dust particles and become heavy, they form clouds. These particles then fall back on the earth's surface in the form of rain, snow, sleet, hail, etc.
So, t
he correct option is 'C'.
The burning of fossil fuels liberates oxygen.
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True
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False
Explanation
The process of burning is called combustion.
Combustion consumes oxygen.
The burning of fossil fuels liberates carbon dioxide.
So, the given statement is false.
Evaporation is a _____________ process.
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Cooling
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Heating
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Can't tell - it depends on the temperature
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Both A and C
Explanation
Evaporation is a process in which heat is required to convert water into water vapour.
The correct option is B.
Assertion: Ozone is destroyed by CFCs in the upper stratosphere.
Reason: Ozone hole increases the amount of UV radiation reaching the earth.
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Assertion and reason are correct , but the reasons is not the explanation for the assertion
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Assertion is false, but the reason is correct
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Assertion and reason are incorrect, Assertion and reason are both correct
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And the reason is the correct explanation for the assertion
Explanation
The upper stratosphere consists of ozone $$(O_3)$$, which protect us from harmful ultraviolet (UV) radiations coming from the sun.
When CFC reacts with ozone it breaks the molecule of ozone resulting in ozone layer depletion.
If the greenhouse effect or global warming remains unchecked, it alter:
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sea levels
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ozone layer
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rainfall
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temperature
Explanation
Global warming is caused by the release of greenhouse gases such as carbon dioxide into the atmosphere. Greenhouse gases warm the atmosphere that increases temperature and can cause other effects such as the sea-level rise and changes in rainfall and storminess. Current levels of greenhouse gases in the atmosphere are unprecedentedly high.
$$\mathbf{Hence\ the\ correct\ answer\ is\ option\ ((A)\ (C)\ and\ (D))}$$
Which process takes place in winters when the snow falls?
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Evapo-transpiration
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Condensation
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Precipitation
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Transpiration
Explanation
Precipitation is any liquid or frozen water that forms in the atmosphere and falls back to the Earth. During winters, the atmosphere is cold and thus rather than rain, the droplets freeze and fall in the form of snow.
Earth is protected from UV-radiations by:
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ozone layer
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nitrogen layer
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carbon dioxide
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oxygen layer
Explanation
The ozone layer refers to a region of earth's stratosphere that absorbs most of the sun's ultraviolet (UV) radiation.
It contains high concentration of ozone ($$O_3$$).
What makes sea water not to be safe for drinking?
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High salt concentration
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High minerals
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Marine water pollution
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Density of sea water
Explanation
Seawater
is toxic to humans because our body is unable to get rid of the
salt
that comes from
seawater
. Our body normally gets rid of excess
salt
by having the kidneys produce urine, but it needs fresh water to dilute the
salt
in our body and for the kidneys to work efficiently.
So the correct answer is option A.
Air pollution can lead to:
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Acid rain
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Heart diseases
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Allergies
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All of the above
Explanation
Air pollution refers to the increased amount of harmful substances in the air like suspended particles of unburnt carbon and hydrocarbons in the air, oxides of nitrogen and sulphur, etc.
There are several adverse effects of air pollution.
Acid rain which is caused when the oxides of nitrogen and sulphur combine with rainwater and become acidic can harm the building and monuments and can cause skin cancer and allergies.
Regular breathing of polluted air can lead to allergies, heart diseases, and cancer.
Also, the suspended particles in the air can lead to various respiratory troubles.
So, the correct option is 'D'.
Water enters atmosphere by
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Filtration
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Evaporation
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Precipitation
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Weathering
Explanation
Evaporation is the process by which water from all the water bodies and land evaporates to form water vapours and enter the atmosphere to form clouds.
The correct option is B.
Earth's temperate is affected by:
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The loss of precipitation
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The loss of heat
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The loss of evaporation
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The loss of sunlight
Explanation
The atmosphere prevents the sudden increase in temperature during the daylight hours. And during the night, it slows down the escape of heat into outer space. Think of the moon, which is about the same distance from the Sun that the Earth is. Despite that, on the surface of the moon, with no atmosphere, the temperature ranges from –190° C to 110° C.
So, if there were no atmosphere, loss of heat would highly affect earth's temperature.
What would happen if earth had no atmosphere?
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Earth would be below freezing
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There would be no existence
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There would be no length of the day
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All of above
Explanation
If there were no atmosphere, there would be no existence of life. Examples are Venus and Mars.
During summer, Boojho carries water in a transparent plastic bottle to his school. One day he left his bottle in the school. The bottle still had some water left in it. The following day, he observed some water droplets on the inner surface of the empty portion of the bottle. These droplets of water were formed due to
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boiling and condensation.
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evaporation and saturation.
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evaporation and condensation.
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condensation and saturation.
Explanation
In summers, the water in the plastic bottles gets heated and evaporates. This evaporated water collides with the cover of the bottle and gets condensed to form water droplets. These water droplets then get collected on the empty portion of the bottle.
Hence, the correct answer is option (c) evaporation and condensation.
In an activity, a teacher dissolved a small amount of solid copper sulphate in a tumbler half-filled with water. Which method would you use to get back solid copper sulphate from the solution?
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Decantation
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Evaporation
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Sedimentation
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Condensation
Explanation
On evaporating the solution, only the water will be evaporated, and solid copper sulphate will be left.
Hence, the correct answer is option (b) Evaporation.
Water can be separated from salt by evaporation.
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True
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False
Explanation
Water can be separated from salt by evaporation.
Hence, the given statement is true.
Paheli asked for a glass of water from Boojho. He gave her a glass of ice-cold water. Paheli observed some water droplets on the outer surface of the glass and asked Boojho how these droplets of water were formed? Which of the following should be Boojhos answer?
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Evaporation of water from the glass.
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Water that seeped out from the glass.
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Evaporation of atmospheric water vapour.
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Condensation of atmospheric water vapour.
Explanation
The surface ice-cold glass, when exposed to air, forms water droplets on the outer surface of glass because the water which is in the form of vapour in the atmosphere gets condensed.
Hence, the correct answer is option (d) Condensation of atmospheric water vapour.
Oxygen is harmful for:
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Ferns
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Nitrogen fixing bacteria
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Chara
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Mango tree
Explanation
Oxygen is harmful for anaerobic bacteria. Among the given options, only Nitrogen fixing bacteria is an example of anaerobic bacteria.
Hence, Option "B" is the correct answer.
In Ozone, number of Oxygen atoms are:
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3
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2
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1
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4
Explanation
The chemical formula of ozone is $$O_3$$
Water exists in the form of
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Saline water
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Fresh water
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Water vapour
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All of these
Explanation
Water occupies a very large area of the Earth's surface and is also found underground. Some amount of water exists in the form of water vapour in the atmosphere. Most of the water on Earth's surface is found in seas and oceans and is saline.
Freshwater is found frozen in the ice caps at the two poles and on snowcovered mountains. The underground water and the water in rivers, lakes, and ponds are also fresh.
Hence, the correct option is D.
Life is not possible without water.
Is the above statement true or false?
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True
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False
Explanation
All cellular processes take place in a water medium. All the reactions that take place within our body and within the cells occur between substances that are dissolved in water. Substances are also transported from one part of the body to the other in a dissolved form. Hence, organisms need to maintain the level of water within their bodies in order to stay alive. Terrestrial life-forms require fresh water for this because their bodies cannot tolerate or get rid of the high amounts of dissolved salts in saline water. Thus, water sources need to be easily accessible for animals and plants to survive on land.
Hence the statement is true.
Western Ghats have high biodiversity because
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They receive abundant rainfall
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They are least populated
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They are near the sea
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All of these
Explanation
Water is essential for maintaining life and biodiversity. Western Ghats are one of the regions with the highest biodiversity in India because they receive plenty of rainfall throughout the year and are covered by evergreen forests.
Hence the correct option is A.
Terrestrial life forms do not need much water.
Is the above statement true or false?
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True
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False
Explanation
Terrestrial life-forms require fresh water for this because their bodies cannot tolerate or get rid of the high amounts of dissolved salts in saline water. Thus, water sources need to be easily accessible for animals and plants to survive on land.
Hence the statement is false.
Freshwater is only found in rivers, lakes and underground.
Is the above statement true or false?
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True
0%
False
Explanation
Freshwater is found frozen in the ice caps at the two poles and on snow-covered mountains.
The underground water and the water in rivers, lakes, and ponds are also fresh.
However, the availability of freshwater varies from place to place.
Hence, the statement is false.
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