RBSE Class 7 Science Important Questions Chapter 17 Forests: Our Lifeline

Rajasthan Board  RBSE Class 7 Science Important Questions  Chapter 17 Forests: Our Lifeline  Important Questions and Answers.

RBSE Class 7 Science Chapter 17 Important Questions Forests: Our Lifeline 

Multiple Choice Questions

Question 1. 
Which among the following animals are not typically forest dwellers?
(a) Sheep 
(b) Elephant
(c) Fox 
(d) Deer
Answer:
(a) Sheep 

Question 2. 
Mushrooms derive their nutrition from:
(a) dead leaves 
(b) air 
(c) soil 
(d) humus
Answer:
(d) humus

Question 3. 
Rubber is manufactured from latex which is obtained from?
(a) bark of trees 
(b) roots of trees 
(c) shrubs 
(d) herbs
Answer:
(a) bark of trees

Question 4. 
Plants release 02 through :
(a) photosynthesis
(b) soil and water
(c) animals and plants
(d) nitrogen fixation
Answer:
(a) photosynthesis

Question 5. 
Which of the following is not obtained from wood? 
(a) pencil 
(b) paper
(c) matchstick 
(d) thermocol
Answer:
(d) thermocol

Question 6. 
The branched part of a tree above a stem is called:
(a) canopy 
(b) crown
(c) understorey 
(d) roof
Answer:
(b) crown

Fill in the blanks

Question 1. 
Often, a bunch of.................is seen sprouting on a heap of animal droppings in a forest.
Answer:
seedling

Question 2. 
.................of trees come in various shapes and sizes.
Answer:
Crowns

Question 3. 
Forests provide the food and.................to the animals.
Answer:
shelter

Question 4. 
The part of topsoil which is composed of decomposed remains of animals or leaves is called.................
Answer:
humus

Question 5. 
Forest is a dynamic.................entity.
Answer:
living

State Whether True or False

Question 1. 
If forests disappear, the amount of C02 in the air increases.
Answer:
True

Question 2. 
Decomposers are organisms that help in the dispersal of seeds.
Answer:
False

Question 3. 
Forest influences the water cycle, climate and air quality.
Answer:
True

Question 4. 
The floors of the forest are spongy due to the presence of special mushrooms.
Answer:
False

Question 5. 
Forests are non-renewable natural resources.
Answer:
False

Match the following

Column I	Column II
1. Dropping	(a) Timber
2. Matchstick	(b) Canopy
3. Understorey	(c) Vulture
4. Rainwater	(d) Water cycle
5. Scavenger	(e) Regeneration
6. Decomposer	(f) Deforestation
7. Transpiration	(g) Global warming
8. Afforestation	(h) Micro-organism
9. Cattle grazing	(i) Identification
10. Carbon dioxide	(j) Soil erosion

Answer:

Column I	Column II
1. Dropping	(c) Vulture
2. Matchstick	(j) Soil erosion
3. Understorey	(i) Identification
4. Rainwater	(a) Timber
5. Scavenger	(b) Canopy
6. Decomposer	(d) Water cycle
7. Transpiration	(e) Regeneration
8. Afforestation	(f) Deforestation
9. Cattle grazing	(g) Global warming
10. Carbon dioxide	(h) Micro-organism

Very Short Answer Type Questions

Question 1. 
List some non-wooden examples of products obtained from forests. 
Answer:
Non-wooden products : 

1. Rubber, 
2. Wax, 
3. Gum, 
4. Honey, 
5. Animal fodder, 
6. Medicinal plants.

Question 2. 
Give two non-conventional modes of identifying the presence of an animal in forest area.
Answer:
Identification of animals by : 

1. Animal footprints 
2. Animal droppings. 

Question 3. 
Do all forest types have the same type of vegetation?
Answer:
No, all forests have different vegetation because of their different climatic conditions and soil composition.
 
Question 4. 
Name five trees commonly found in forests.
Answer:
Trees in forests are : 

1. Peepal, 
2. Sheesham, 
3. Teak, 
4. Neem, 
5. Bam-boo.

Question 5. 
Why is the forest's floor dark in color?
Answer:
The Forest floor is dark in color because of the decompositions of animal and plant matter into dark-colored humus.

Question 6. 
Arrange in the increasing order of their height: a peepal tree, a tulsi plant, bamboo. 
Answer:
Tulsi < bamboo < peepal tree.

Short Answer Type Questions

Question 1. 
Give examples of some wild animals and insects present in a forest.
Answer:
Wild animals : 
Elephant, jackal, bear, bison, porcupine etc.

Insects : 
Ants, spiders, beetle, butterfly, worms, etc.

Question 2. 
How are plants arranged in an understorey?
Answer:
Within the understorey, the tall trees constitute the upper, layers, the shrubs and tall grasses the middle layers, and the herbivorous plants form the lowest layer. 

Question 3. 
What is a food chain? Give an example of a food chain.
Answer:
A food chain is a linear sequence of organisms through which food and energy pass as one organism consumes another organism. 
Food chain : 
Grass→ Grasshopper →Frog →Snake →Peacock. 

Question 4. 
How deforestation can be prevented?
Answer:
Deforestation can.be prevented by :

1. planned to harvest
2. afforestation
3. preventing forests trees
4. protecting plants from insects
5. protection from grazers.

Question 5. 
List five uses of forests. 
Answer:
Forests have many uses, five of which are:

1. Balance the ratio of oxygen and carbon dioxide in the atmosphere.
2. Reduce the chances of soil erosion and flooding.
3. Help in maintaining the height of the water table.
4. Help to reduce the noise and heat in their surroundings. 
5. Provide shelter, food, and a hiding place to several species of animals.

Question 6. 
Why are forests called dynamic living entity?
Answer:
Forests are called a dynamic living entity because everything that resides within it - plants or animals are in dynamic equilibrium. The food chain is in continuous function and all that is produced hence is returned to the soil.

Question 7. 
How can soil erosion be prevented? 
Answer:
Soil erosion can be prevented by planting more trees, as the roots of trees help to bind the soil and prevent it from being carried away by the rainwater.

Long Answer Type Questions

Question 1. 
What are the ways in which a forested area is damaged?
Answer:

1. Forest fires due to lightning or carelessness from mankind. E g. burning of matchsticks.
2. The quick spread of infections of plants.
3. Overgrazing by cattle and other farm animals.
4. Falling of trees to obtain forest land for other purposes like agriculture, roadways or buildings.
5. Cutting of trees to make various wooden products.

Question 2. 
Why are forests called the ‘green lungs of a city?
Answer:
Forests are called the 'green lungs of a city because just like lungs exchange gases, they also do the same. They maintain the balance between carbon dioxide and oxygen in the environment by their dual processes i.e. photosynthesis and respiration. They absorb carbon dioxide from the environment and produce oxygen that we all breathe in. Hence, they are called green lungs.

Question 3. 
What is global warming? How do forests prevent it?
Answer:
Global warming is the gradual rise in the Earth’s overall temperature due to the greenhouse effect caused by the increased levels of carbon dioxide and other air pollutants. Since, plants take up carbon dioxide during the process of photosynthesis thus, decreasing the level of carbon dioxide in the atmosphere. Therefore, we can say that forests prevent global warming.

Question 4. 
How do forests affect the temperature of an area?
Answer:
Forests are richly populated with trees that absorb water from the soil and return it to the atmosphere by transpiration in the form of water vapor. Hence, it plays an important role in the water cycle which helps in cloud formation and increases rainfall in nearby areas. The moisture in the air also reduces the temperature of the surroundings. Secondly, they absorb C02 which reduces global warming and hence prevents the rise in temperature.