7th Grade > Chemistry
FORESTS OUR LIFELINE MCQs
Total Questions : 81
| Page 1 of 9 pages
Answer: Option B. -> desertification
:
B
The process by which fertile land becomes arid and finally converts to a desert, as a result of deforestaion, or inappropriate agriculture is known as desertification.
:
B
The process by which fertile land becomes arid and finally converts to a desert, as a result of deforestaion, or inappropriate agriculture is known as desertification.
Answer: Option A. -> True
:
A
Plants are primary producers of food. Herbivorous animals depend directly on plants for their food. Carnivorous eat these herbivouros animals and gain energy. Thus, ultimately they too depend on plants for food and energy.
:
A
Plants are primary producers of food. Herbivorous animals depend directly on plants for their food. Carnivorous eat these herbivouros animals and gain energy. Thus, ultimately they too depend on plants for food and energy.
:
Canopy isformedby the mass of intertwined branches, twigs and leaves of mature trees.The branches of tall trees look like a roof over the other plants in the forest.
:
Each point: 1 Mark
1)Forests provide us with oxygen.
- A single mature, leafy tree is estimated to producea day's supply of oxygen for 5to 10 people on an average.
2) They provide habitat to a large number of plants,animals and humans.
- They provide almost 80% of biodiversity on land.
- Almost 2 billion people rely on forests.
3) Forests help in bringing good rainfall in neighboring areas.
4) They are goodsources of medicinal plants, timber and many other useful products.
5) They preventsoil erosion, regulate the flow of rivers and reduce the frequency and intensity of floods.
- Tree roots are very helpful duringheavy rainfall, especially for low-lying areas like river plains. They help the ground absorb theflash flood, reducing soil loss and property damage by slowing the flow.
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 C. -> desertification
:
C
Turning forests into pastures leads to soil erosion. As a result of which, removal of the top layer of soil exposes the lower, hard and rocky layers. This soil has less humus and is less fertile. Gradually the fertile land gets converted into deserts. This is called desertification.
:
C
Turning forests into pastures leads to soil erosion. As a result of which, removal of the top layer of soil exposes the lower, hard and rocky layers. This soil has less humus and is less fertile. Gradually the fertile land gets converted into deserts. This is called desertification.
Answer: Option A. -> Dead plants and animals
:
A
Decomposers feed on dead plants and animal tissues. They convert them into humus. This activity also helps in increasing the soil fertility.
:
A
Decomposers feed on dead plants and animal tissues. They convert them into humus. This activity also helps in increasing the soil fertility.
Answer: Option B. -> lungs
:
B
Forestsabsorb the carbon dioxide released by animals from the atmosphere and produce oxygen for respiration. In this manner they maintain the balance of these gases in the atmosphere. Hence, they are known as the green lungs of the Earth.
:
B
Forestsabsorb the carbon dioxide released by animals from the atmosphere and produce oxygen for respiration. In this manner they maintain the balance of these gases in the atmosphere. Hence, they are known as the green lungs of the Earth.
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
The complete order offood 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 thesnakes.
:
A
The complete order offood 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 thesnakes.
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