Free Natural Resources 02 Practice Test - 9th Grade 

Question 1

Percentage of nitrogen and oxygen in the air is ____ respectively.

A.

70% and 30% approx

B.

80% and 20% approx

C.

78% and 21% approx

D.

60% and 40% approx

SOLUTION

Solution : C

Air is a mixture of many gases. It is primarily composed of approx 78% nitrogen and 21% oxygen with only small concentration of other gases such as carbon dioxide and argon.

Question 2

Which is the outermost layer of the Earth?

A.

Crust

B.

Mantle

C.

Outer core

D.

Inner core

SOLUTION

Solution : A

The crust is the outermost layer of the Earth followed by mantle. The outer core is located around 1800 miles under the crust and approximately 1400 miles thick. Inner core is the center and is  the hottest layer of the Earth. 

Question 3

The addition of harmful or toxic chemicals to the soil is called _________ .

A. soil pollution
B. soil weathering
C. soil formation
D. desertification

SOLUTION

Solution : A

The addition or removal of constituents from soil, changing its natural composition is called soil pollution. There is a substantial decrease in soil fertility due to soil pollution. This is because of the addition of contaminants that alters the chemistry of the soil.

Question 4

Which of the following contribute to the carbon cycle?

A.

Photosynthesis

B.

Burning of fossil fuel

C.

Transpiration

D.

Respiration  

SOLUTION

Solution : A, B, and D

The given image depicts carbon cycle.
Photosynthesis is a biological process used by plants to prepare food with the help of sunlight, water and carbon dioxide. 
Burning of fossil fuel (combustion) and respiration release carbon dioxide into the atmosphere. Hence, these processes are involved in carbon cycle.
Transpiration is the process by which water vapour is lost from the aerial parts of a plant. It is a part of the water cycle.

Question 5

Plants use nitrogen in the form of _____.

A. Nitric oxides
B. Nitrous oxides
C. Nitrides
D. Nitrates

SOLUTION

Solution : D

Plants cannot use the atmospheric nitrogen directly. Nitrogen fixation is a biological process and the initial stage of nitrogen cycle which converts atmospheric nitrogen into ammonia. This ammonia is converted into nitrite and then into nitrate by the process of nitrification. Nitrate is the form of nitrogen which is directly absorbed and used by the plants for making amino acids and proteins.

Question 6

Why is the atmosphere essential for life?

A. It acts as a blanket and keeps the average temperature of the Earth.
B. It contains all the gases which are essential for sustaining life on the Earth.
C. Ozone layer present in the atmosphere prevents harmful UV rays from reaching the Earth.
D. Water cycle is not possible without atmosphere.

SOLUTION

Solution : A, B, C, and D

The air that covers the whole of the Earth like a blanket, is called the atmosphere. Atmosphere is essential for life because of the following reasons:
i) It acts as a blanket and keeps the average temperature of the Earth.
ii) It contains all the gases which are essential for sustaining life on the Earth.
iii) Ozone layer present in the atmosphere prevents harmful UV rays from reaching the Earth.
iv) Water cycle is not possible without atmosphere.

Question 7

Ozone layer protects the life on Earth from the harmful effects of UV radiations by absorbing them. 

A. True
B. False

SOLUTION

Solution : A

Ozone layer is present in the lower parts of the stratosphere. It absorbs all the ultraviolet radiations and does not allow them to reach Earth's surface, thus protecting all living organisms from the harmful effects of UV radiations. 

Question 8

Which of the following are true statements regarding lichens?

A. They help in the formation of soil.
B. They are dead and decayed organisms.
C. They can be found on the surface of rocks.
D. They degrade the fertility of soil.

SOLUTION

Solution : A and C

Lichens grow on the surface of rocks. They release certain substances that cause the rock surface to powder down and form a thin layer of soil. They also enrich the soil by trapping water, dust and silt.

Question 9

Which of the following factors influence the direction of wind?

A. Presence of mountain ranges
B. Rotation of the earth
C. Uneven heating of atmosphere
D. Pressure variations in the region

SOLUTION

Solution : A, B, C, and D

The wind is formed when the air moves from one region to another region. In coastal regions, when the land heats up during day time, it creates a low pressure region above the land. As the temperature over a region increases, the pressure decreases in that region. Therefore, air above the sea moves towards the direction of low pressure region. The wind moves from high pressure to low pressure region.
The other factors which effect the direction of wind are the rotation of the earth and the presence of mountain regions in the direction of wind. Hills and mountain ranges will act as a barrier, holding back the wind and deflecting it to other directions.

Question 10

The total water present on earth is called as 'hydrosphere'. It includes:

A.

Oceans

B.

Glaciers

C.

Valleys

D.

Atmospheric moisture

SOLUTION

Solution : A, B, and D

Hydrosphere of the Earth includes water that is on its surface, underground, and in the air. It also means water in all the states - ice, liquid and vapour. Hydrosphere includes oceans, glaciers, rivers, lakes, ponds, atmospheric moisture and underground water. 

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