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Natural Resources

Class 8th Science Part I Karnataka Board Solution

Exercises
Question 1.

One of the following does not belong to the group
A. water

B. forests

C. petrol

D. soil


Answer:

All other options forests, water and soil are renewable sources of energy but petrol is a non renewable source of energy which cannot be replenished with time. Therefore, petrol does not belong to the group.


Question 2.

Government has banned hunting of wild animals. This helps to
A. maintain biodiversity

B. promote tourism

C. provide food to animals

D. maintain soil fertility


Answer:

Ban on hunting and poaching of wild animals was an


initiative of government in order to conserve the biodiversity. Since,


due to these activities many species are suffering from the threat of


extinction and extinction of these species has a bad effect on our


ecosystem. So, in order to maintain the ecological balance and to conserve biodiversity government has banned hunting and poaching.


Question 3.

Fill in the blanks with suitable words :

Resources that get replenished in nature are called ___________.’


Answer:

Resources that get replenished in nature are called Renewable natural resources.


Explanation: Replenishment of resources refers to the restoring of resources. There are certain resources in nature which get restored from time to time in order to maintain a flow. Since, these resources get renewed and replenished they known as renewable natural resources.


For example- Solar energy, wind energy is example of renewable natural resources.



Question 4.

Fill in the blanks with suitable words :

Petrol, and kerosene are ___________ forms of natural resources.


Answer:

Petrol and kerosene are nonrenewable forms of natural resources.


Explanation: Petrol and kerosene are fossil fuels which take million of years for their formation. Since they take such a long time for their formation and we are using them at a high rate they can’t be renewed. Therefore, petrol and kerosene are considered as nonrenewable forms of natural resources.



Question 5.

Fill in the blanks with suitable words :

If there is rise in water table, soil becomes ___________.


Answer:

If there is a rise in water table, the soil becomes saline.


Explanation: There are some salts which remain associated with the water and are responsible for the salinity of the soil. When the rate of entry of water into the soil is higher than the rate it is being used water table starts rising. Due to rise in water table there salts also starts accumulating in soil and due to their accumulation soil becomes saline.



Question 6.

Fill in the blanks with suitable words :

Soil provides ___________ and___________ to terrestrial plants.


Answer:

Soil provides water and minerals to terrestrial plants.


Explanation: Soil is the only source for the land plants to get water and minerals. There are many minerals and nutrients which are present in the soil. Terrestrial plants absorb water and minerals from the soil with the help of root.



Question 7.

Fill in the blanks with suitable words :

An example for renewable resource is ___________.


Answer:

An example of the renewable resource is solar energy.


Explanation: Renewable resources are those natural resources which get replenished from time to time and can be used again and again which refers they are renewed. Solar energy is also one such example which gets replenished from time to time and can be used again and again.



Question 8.

Answer the following:

What are the natural resources?


Answer:

All the things which are useful to us for our survival and other activities and are provided by nature to us are termed as natural resources.

For example- Solar energy, water, forests etc.



Question 9.

Answer the following:

Differentiate between renewable and non-renewable resources.


Answer:

Difference between renewable and non-renewable resources are depicted in the following table:



Question 10.

Answer the following:

List the uses of water.


Answer:

Following are the uses of water:

● It is very much essential as it is required for the survival of each and every species.


● It is required for our various daily activities like drinking, cooking, washing, cleaning etc.


● Agriculture which is an integral part of our life is also not possible without water.


● It is also used to produce energy.


● It is used in fire extinguishers.


● It is used in heat exchange processes.


● Water is the fluid which has no alternative and can’t be replaced by any other fluid. It is required by each and every organism in some amounts. It is a part of our survival.



Question 11.

Answer the following:

What is mining?


Answer:

Mining is a process in which minerals are extracted out from the earth crust.

Minerals are nonrenewable resources which are a result of various geological activities of the earth and are not formed from living matter.


The following picture depicts mining process:




Question 12.

Answer the following:

What happens if too much of fossil fuels are used?


Answer:

If too much fossil fuel is used they will get exhausted one day and the coming generations will be deprived of them.

Fossil fuels are a non renewable source of energy which does not get replenished with time. Formation of fossil fuels requires million of years and thus can’t be replenished. Fossil fuel is a resource which is in limited stock and should be used carefully otherwise we will leave with no fossil fuels. They are a kind of resource whose rate of formation is very slow and the rate of consumption is very high. So, if we won’t use them carefully one day they will be finished.



Question 13.

Answer the following:

A student argues that a nation will be rich if its forests are conserved. Justify.


Answer:

Yes, the student was very true in his argument that a nation will be rich if its forests are conserved.

Forests are a rich source of biodiversity, various other resources like timber, medicines etc are also provided by forests to us. They help in maintain ecological balance as they provide habitat to various organisms and thus help in their conservation. They also help in maintaining the water cycle, preventing soil erosion.

Forests are a kind of wealth which plays important role in the development of a country. If forests are conserved all other environmental problems can be easily prevented therefore a nation will be rich, if its forests are conserved.


Question 14.

Match the following :



Answer:

1. High carbon content- Anthracite


Explanation- Anthracite is the form of coal which contains highest carbon content. It contains 80% carbon content.


2. Renewable resource- Wind


Explanation- Wind is a resource which is replenished from time to time and does not require million of years for its formation. Since it is replenished and can be used again and again it is termed as a renewable source of energy.


3. Low sulphur content- Natural gas


Explanation- Natural gas has very low sulphur content which makes it least polluting source of fuel.


4. Formation of soil- Weathering of rocks


Explanation- Soil is formed from weathering of rocks over a period of time.