7th Grade > Chemistry
FORESTS OUR LIFELINE MCQs
Total Questions : 81
| Page 6 of 9 pages
Answer: Option A. ->
Soil erosion
:
A and B
:
A and B
∙ The forests act as rainwater harvesters, they replenish the ground water and help in maintaining the water cycle.
∙ Desertification refers to the conversion of fertile land into deserts due to deforestation. The roots hold the soil and hence prevent soil erosion which stops desertification.
∙ The oxygen that we breathe in, is also given out by the trees. They take in carbon dioxide and balance these two gases in the atmosphere.
∙ Thus, if forests disappear soil erosion and desertification will occur.
Answer: Option A. ->
Composing humus
:
A and B
Decomposers are organisms that decompose various dead organisms, plants and recycle nutrients and form humus.
:
A and B
Decomposers are organisms that decompose various dead organisms, plants and recycle nutrients and form humus.
Answer: Option A. ->
True
:
A
Plants take up carbon dioxide exhaled by animals and release oxygen inhaled by animals. Thus, forests maintain a balance between the two gases in atmosphere. Deforestation disturbs this balance and increases the amount of carbon dioxide in atmosphere.
:
A
Plants take up carbon dioxide exhaled by animals and release oxygen inhaled by animals. Thus, forests maintain a balance between the two gases in atmosphere. Deforestation disturbs this balance and increases the amount of carbon dioxide in atmosphere.
Answer: Option B. ->
False
:
B
The roots of trees firmly hold the topmost layer of the soil. They do not allow natural forces like wind, water, etc., to carry away the top most fertile layer of the soil easily. Afforestation refers to the planting of trees in an area, which will prevent soil erosion.
:
B
The roots of trees firmly hold the topmost layer of the soil. They do not allow natural forces like wind, water, etc., to carry away the top most fertile layer of the soil easily. Afforestation refers to the planting of trees in an area, which will prevent soil erosion.
Answer: Option B. ->
They provide food and shelter to animals
:
A, B, and C
Forests act as natural absorbers of rainwater, thus they prevent flooding in case of heavy rains. They provide food and shelter to animals. Trees release oxygen and absorb carbon dioxide, hence reduce greenhouse effect.
:
A, B, and C
Forests act as natural absorbers of rainwater, thus they prevent flooding in case of heavy rains. They provide food and shelter to animals. Trees release oxygen and absorb carbon dioxide, hence reduce greenhouse effect.
Answer: Option B. ->
food
:
B and C
Forests provide a natural habitat to a number of organisms, such as insects, birds and animals. It provides them with food, shelter, oxygen, etc. Deforestation leads to their habitat destruction.
:
B and C
Forests provide a natural habitat to a number of organisms, such as insects, birds and animals. It provides them with food, shelter, oxygen, etc. Deforestation leads to their habitat destruction.
Answer: Option B. ->
Increase noise pollution
:
A, C, and D
:
A, C, and D
Forests provide medicinal plants, maintain the flow of water into the streams and also absorb rainwater. Thus, they prevent flooding and maintain water table. Tree parts such as thick branches and leaves effectively absorb noise, hence, they also reduce noise pollution.
Answer: Option C. ->
Kerosene
:
C
Kerosene is not a forest product. It is refined from crude oil or petroleum which is found deep under the earth's surface. All the other products (matchstick, plywood, and paper) are obtained from forest wood.
:
C
Kerosene is not a forest product. It is refined from crude oil or petroleum which is found deep under the earth's surface. All the other products (matchstick, plywood, and paper) are obtained from forest wood.
Answer: Option A. ->
Crown
:
A
The tree crown is the top part of the tree. It contains branches that grow out from the main trunk and supports various leaves.
:
A
The tree crown is the top part of the tree. It contains branches that grow out from the main trunk and supports various leaves.
Answer: Option A. ->
Snake
:
A
:
A
The complete order of food chain is as follows:
Grass → Insects → Frog → Snake → Eagle
Grass is primary producer of food. It prepares its own food. Insects cannot prepare their own food, they eat grass, and are in turn eaten up by frogs. Frog are consumed by snakes. Lastly in this food chain, eagles eat the snakes.
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