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NCERT Solutions For Class 8 Science Chapter 5 Conservation Of Plants: Very Short Answer Questions

Question 1. Can a forest regenerate naturally in a short period?
Answer:

Restoration can take place naturally by leaving the drenched area undisturbed for a long period. During this period, the area re-establishes itself without the interference of human beings.

Question 2. Paheli is curious to know the purpose of making National Parks, Wildlife Sanctuaries, and Biosphere Reserves.
Answer:

National parks, Wildlife sanctuaries, and Biosphere reserves are made to protect the flora and fauna whose numbers are diminishing.

NCERT Class 8 Science Chapter 5 Conservation of Plants VSAQs

Question 3. Animal life is also affected by deforestation. How?
Answer:

The natural habitats of wild animals get destroyed due to deforestation, and they tend to move to other habitats or are left to die without proper shelter.

Question 4. List the factors disturbing the biodiversity of your area. Some of these factors and human activities may disturb the biodiversity unknowingly. List these human activities. How can these be checked?
Answer:

Various factors can disturb the biodiversity of an area, such as volcanic eruptions, earthquakes, thunderstorms, etc. Some human activities, such as deforestation pollution, poaching, etc., also destroy the biodiversity of an area. These human activities can be checked by educating people or applying strict laws.

Question 5. Paheli has heard that some of the endemic species may vanish. Is it true
Answer:

Yes, endemic species may vanish due to the destruction of their habitat, increasing population, and the introduction of new species.

NCERT Solutions for Conservation of Plants Chapter 5

Question 6. Boojho wants to know whether tigers are still found in the forest. He is excited to see a tiger.
Answer:

The Tiger is one of the many species that are slowly disappearing from forests. But the Satpura tiger reserve is unique in the sense that a significant increase in the population of tigers has been seen here.

Question 7. Pahcli wants to know whether only big animals are facing the danger of extinction.
Answer:

No, the small animals are much more in danger of becoming extinct than the bigger animals. This is because the small animals like snakes, frogs, etc., get killed ruthlessly without realising their importance in the ecosystem. They might be small in size, but their role in the ecosystem cannot be ignored.

NCERT Class 8 Science Chapter 9 Friction VSAQs

Question 1. Why is it difficult to move on a wet marble floor?
Answer: On a wot marble Door, the frictional force between the foot and Door decreases to make it slippery, thus we feel difficult to move on a wet wooden marble floor.

NCERT Solutions for Friction VSAQs Class 8

Question 2. State the reason why we slip when we step on a banana peel.
Answer: As we step on a banana peel, there is no grip between our foot and the banana peel due to very less friction. So, we slipped accidentally.

Question 3. Is the friction the same for all the surfaces?
Answer: No, because friction depends on the nature surface in contact.

Question 5. Can you imagine being able to walk at all if there were no friction?
Answer: No, we can’t walk at all if there is no friction.

Question 6. Could you write, if there were no friction between
Answer: No, we wouldn’t be able to write on a blackboard if there were no friction between the chalk and the board.

Question 7. How do you feel if you vigorously rub your palms together for a few minutes?
Answer: We will feel that our hands feel warm. This warmth is caused by a force called friction.

NCERT Solutions for Class 8 Science Friction VSAQs

Question 8. Have you ever thought why the sole of your shoe is grooved?
Answer: It is done to provide the shoes better grip. The groove on shoes increases the friction between the shoes and the floor.

Question 9. Why do you sprinkle fine powder on the carrom board?
Answer: Powder is sprinkled on the carrom board to reduce friction.

Question 10. The pieces of luggage were fitted with the rollers. Explain why?
Answer: To reduce friction, pieces of luggage are fitted with rollers so that even a child can pull the luggage easily.

NCERT Solutions for Friction Chapter 9 VSAQs

Question 11. Can we reduce friction to zero by polishing surfaces or using a large amount of lubricant?
Answer: No, friction can never be eliminated. Some irregularities are always there.

Question 12. Where do you think scientists got hints for the streamlined shapes?
Answer: Scientists got hints for the streamlined shapes from the body shapes of birds and fishes who have to move about in fluids all the time.

Question 13. Do you find any similarity in the shape of an aeroplane and that of a bird?
Answer: Yes, both have streamlined bodies, which help them to move easily through fluid.

NCERT Solutions For Class 8 Science Chapter 5 Conservation Of Plants SAQs

Question 1. Boojho wants to know if there is any permanent solution to the problem of deforestation.
Answer:

The permanent solution to the problem of deforestation is reforestation. It is the restocking of the destroyed forests by planting new trees.

Question 2. Difference between the following.

1. Wildlife sanctuary and Biosphere reserve
2. Zoo and Wildlife Sanctuary
3. Endangered and Extinct Species
4. Horn and Found

Answer:

1. The Difference between a wildlife sanctuary and a biosphere reserve is as follows:

NCERT Class 8 Science Chapter 5 Conservation of Plants SAQs

2. Differences between the zoo and a wildlife sanctuary are as follows

3. The difference between an endangered species and an extinct species is as follows

4. The difference between flora and fauna is as follows

NCERT Solutions for Conservation of Plants Chapter 5

Question 3. Discuss the effects of deforestation on the following.

1. Wild animals
2. Environment
3. Villages (rural areas)
4. Cities (urban areas)
5. Earth
6. The next generation

Answer:

1. Wild animals:

Deforestation destroys the habitat of wild animals. This leads them to the danger of extinction.

2. Deforestation:

Increases the amount of CO₂ in the environment, which increases the temperature. Due to this, the water cycle is disturbed, which may lead to drought. It also reduces the water holding capacity of soil, which leads to floods.

3. Villages (rural areas):

The lifestyle of villagers depends much on forests for wood, vegetables, fruits, meat, grass, etc. Deforestation leads their life to struggles for all of these. Also, their life become threatened by wild animals.

4. Cities (urban areas):

Deforestation causes drought, flooding, and environmental pollution, which affect the lives of people living in cities.

5. Earth:

The various gases on Earth, like water, oxygen, and carbon dioxide, are disturbed due to deforestation. It increases the temperature and pollution level on the Earth and is also the main cause of global warming.

6. The next generation:

The major effect of deforestation on the next generation is the limitation of natural resources like wood, oxygen, water, etc.

Conservation of Plants SAQs Class 8 NCERT Solutions

Question 4. What will happen if
Answer:

1. We go on cutting trees.
Answer:

If we continue cutting trees, then

1. Many animals will lose their shelters.
2. There would be a scarcity of materials like fruits, paper, which we get from forests.
3. Floods and droughts will become more frequent.
4. Earth will lose its most fertile layer and transform into a desert.

2. The habitat of an animal is disturbed.
Answer:

The habitat of an animal provides it with necessities such as shelter, food, and protection. If the habitat of an animal is disturbed, then it will be forced to go to other places in search of food and shelter. As a result, the animal could be killed.

3.  The top layer of soil is exposed.
Answer:

Removal of the top layer of the 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. It is called desertification.

Question 5. Answer in brief.
Answer:

1. Why should we conserve biodiversity?
Answer:

We should conserve biodiversity because every organism in nature plays an important role in balancing of natural system.

2.  Protected forests are also not completely safe for wild animals. Why?
Answer:

Protected forests are not completely safe for wildlife because some local people kill animals on a large scale for their valuable skin, teeth, etc.

SAQs for Conservation of Plants Chapter 5 Class 8

3.  Some trials depend on the Jungle. How?
Answer:

Some tribals depend on the jungle because they get most of their resource to live from the jungle, like shelter, wood, food, etc.

4. What are the causes and consequences of deforestation?
Answer:

The main causes of deforestation are the cutting of trees for wood and the use of land for industries and houses. Its consequences are flooding, drought, extinction of species, and many more harmful activities.

5. What is the Red Data Book?
Answer:

The Red Data Book is a source book that maintains an international list of all endangered animals and plant species.

6. What do you understand by the term migration?
Answer:

Migration refers to the movement of an organism or a group oforganisms from its natural habitat to another place at a particular time because of climatic change. Birds that cover long distances to reach another land are known as migratory birds.

Question 6. To meet the ever-increasing demand in factories and for shelter, trees are being continually cut down. Is it justified to cut trees for such projects? Discuss and prepare a brief report.
Answer:

The continuous cutting of trees is not justified for any project because it leads to deforestation, desertification, flooding, and danger to the lives of wild animals. It also disturbs the balance of nature.

Question 7. How can you contribute to the development of the green wealth of your locality? Mnko, n list of notions to be taken by you.
Answer:

We can contribute to the maintenance of the green wealth of our locality by taking these actions.

1. Taking care of the plants and trees growing in or around the locality.
2. Encourage people to plant more trees by informing them about the importance of growing trees.

NCERT Solutions for SAQs on Conservation of Plants

Question 8. Find out about the National parks in your state. Identify and show their location on the outline map of India.

Answer:

One of the National parks located near Delhi is the Jim Corbett National Park in Uttarakhand.

Question 9. Why should paper be saved? Prepare a list of ways by which you can save paper.
Answer:

Paper should be saved because it takes our important natural resource, i.e., trees, to make it (around 17 full-grown trees to make one tonne of paper). Trees, as we know, are important to maintain a balance in nature.

Therefore, to save trees and prevent the impact of their loss in the living world, we need to save paper. We can save paper by following these ways

1. Paper should be recycled.
2. Use both sides of a paper for writing purposes.
3. Spread awareness regarding the value of saving paper.

NCERT Solutions For Class 8 Science Chapter 5 Conservation Of Plants Long Answer Question

Question 1. The Gangetic Dolphin is a freshwater aquatic mammal. Which of these measures will protect the Gangetic Dolphin species?

Circle ‘Yes’ or ‘No’ for the correct response

Answer: No, No, Yes

Question 2. The table shows an example of the different types of threats to the Gangetic Dolphin.

Surface runoffs containing pesticides also threaten the survival of the Gangetic Dolphin. Which type of threat in the table does this belong to? Explain your answer.

Answer:

Surface runoffs containing pesticides are an example of water pollution. Pesticides are harmful chemicals that pollute water bodies and threaten the survival of the Gangetic Dolphin.

NCERT Class 8 Science Chapter 5 Conservation of Plants LAQs

Question 3. The table shows two groups of natural resources.

1. Radha visited a protected forest area where she could enter at her own will and collect samples of herbs. Which type of protected forest area did Radha visit? Explain your answer.

Answer:

Radha visited wildlife sanctuary as in the wildlife sanctuary, where visitors are allowed without permission and can collect plant samples.

NCERT Solutions for Conservation of Plants Chapter 5

2. Which of these statements is supported by the table?

1. Mining is allowed in National parks
2. A zoo is an example of a wildlife sanctuary
3. National parks are larger than wildlife sanctuaries
4. Wildlife sanctuaries are always found in river basins

Answer: 3. National parks are larger than wildlife sanctuaries.

NCERT Class 8 Science Chapter 9 Friction Short Answer Questions

Question 1. Two friends are trying to push a heavy load as shown in figure below. Suggest a way which will make this task easier for them.

NCERT Solutions for Friction SAQs Class 8

Answer:

Both friends can put rollers below the heavy load. Since the rolling friction is smaller than the sliding friction. Therefore, putting rollers below the heavy load will make this task easier for them.

Question 2. It is easier to move the box from rest or to move it when it is already in motion. Explain why?
Answer:

When the object is at rest, we have to apply more force to overcome interlocking between irregularities. On the other hand, when the object starts moving, the contact points on its surface do not get enough time to lock into the contact points on the ground. So, it is easier to move the block when it is already in motion.

Question 3. Four children were asked to name forces due to rolling, static, and sliding frictions in a decreasing order. Their arrangements are given below. Choose the correct arrangement.

1. Rolling, static, sliding
2. Rolling, sliding, static
3. Static, sliding, rolling
4. Sliding, static, rolling

Answer:

3. We know that static friction is more powerful than all other frictions. Hence, it will take first place in decreasing order. Similarly, sliding friction is smaller than static friction but greater than rolling friction. Thus, the decreasing order of the forces due to these frictions is as follows

NCERT Solutions for Class 8 Science Friction SAQs

Static > Sliding > Rolling

Question 4. Alida runs her toy car on the dry marble floor, the wet marble floor, the newspaper, and a towel spread on the floor. The force of friction acting on the car on different surfaces in increasing order will be

1. Wet marble floor, dry marble floor, newspaper, and towel
2. Newspaper, towel, dry marble floor, wet marble floor
3. Towel, newspaper, dry marble floor, wet marble floor
4. Wet marble floor, dry marble floor, towel, newspaper

Answer:

1. The correct arrangement is as follows:

Wet marble floor, dry marble floor, newspaper, and towel.

Question 5. Suppose your writing desk is tilted a little. A book kept on it starts sliding down. Show the direction of the frictional force acting on it.
Answer:

A book kept on a tilted writing desk starts sliding down. The direction frictional force is in the opposite direction, thus the frictional force will act in an upward direction.

Question 6. You spill a bucket of soapy water on a marble floor accidentally. Would it make it easier or more difficult for you to walk on the floor? Why?
Answer:

After spilling a bucket of soapy water on a marble floor, it would be more difficult for us to walk on the floor. Because the layer of soapy water reduces the friction and the foot cannot make a proper grip on the floor.

NCERT Solutions for Friction Chapter 9 SAQs

Question 7. Explain why sportsmon uao ahoea with splkea?
Answer:

Sportsmen use shoes with spikes in order to avoid slipping in the field. The spikes in the shoes increase the friction, so they can run on the ground easily.

Question 8. Iqbal has to push a lighter box, and Scema has to push a similar heavier box on the same floor. Who will have to apply a larger force and why?
Answer:

The heavy object will be pressed hard against the opposite surface and produce more friction. So, Secma will have to apply a larger force due to more friction.

Question 9. Explain why sliding friction is less than the static friction.
Answer:

We know that friction is caused by the interlocking of irregularities on the two surfaces.

In case of static friction, interlocking between two objects is very strong but in case ofsliding friction, there is less time ofgetting interlocked with each other. Thus, the sliding friction is less than the static friction.

NCERT Class 8 Science Chapter 9 Friction SAQs

Question 10. Give examples to show that friction is both a friend and a foe.
Answer:

Friction as a friend

1. It allows us to walk comfortably.
2. It allows us to minimise the speed or to stop the moving objects.
3. It allows us to write on a board with chalk.

Friction as a foe

1. It causes wear and tear in objects.
2. It causes damage to the parts of machines.
3. It does not allow the free movement of objects.

Friction Class 8 NCERT SAQs

Question 11. Explain why objects moving in fluids must have special shapes.
Answer:

The frictional force exerted by fluids is also called drag. When objects move through fluids, they have to overcome the friction acting on them. In this process, they lose their energy.

Efforts are made to minimise friction. So, objects are given special shapes, and this type of shape is known as a streamlined shape.

NCERT Class 8 Science Chapter 7 Reaching The Age Of Adolescence LAQs

Question 1. A few days back, Shradhaa, a student of class Vth, was driving a car. She went to a crop field. The road level was just above the level of the ploughed field. As she wanted to stop the slow-moving car, the brakes failed to work. Suddenly, she turned the car towards the ploughed field. After some time, the car came to rest.

1. Shradha turned the car towards the ploughed field. Explain why?
Answer:

She turned her car towards the ploughed field to protect herself from an accident.

NCERT Solutions for Friction LAQs Class 8

2. Explain how the car came to rest after covering some distance in the ploughed field.
Answer:

The car moved from the road to the ploughed field, so the force of friction between the tyre and the ground surface suddenly increased. Because the large number of irregularities reduces the movement of the tyre. Thus, the car came to a rest.

3. Mention the values that Shradha exhibits here.
Answer: The values displayed by Shradha are intelligence and awareness.

Question 2. In a Physics classroom, a teacher told to his students that when a cricket player wants to catch a ball then he first rubs his hands. Thus, there is less chance of slipping the ball from the hands.

1. Explain the reason for not slipping of ball from the hand.
Answer:

The player rubs his hand, due to which the palms become warm which absorbing the moisture from the surface and making the surface rough. So, due to the roughness of the hands, the ball may get a better grip between the hands and will not slip.

NCERT Solutions for Class 8 Science Friction LAQs

2. If the player makes his hands oily instead of rubbing them, would he be able to catch the ball?
Answer:

The player makes the palm surface oily. The number of irregularities decreases, and the surface becomes smooth. So, the ball slips off easily from the hand.

3. Mention the type of teaching skills of the teacher that is being represented here.
Answer:

As, teacher wants to teach the students through easy examples. So, this act of teaching shows the experience and ideality of the teacher.

Question 3. Explain with the help of an example that heat is produced by friction.
Answer:

As friction opposes the relative motion between the two surfaces, it produces heat. So, when we rub our hands together vigorously for a few minutes, we feel heat. Similarly, when we strike a matchstick against the rough surface, it catches fire.

NCERT Solutions for Friction Chapter 9 LAQs

Question 4. We have two identical metal sheets. One of them is Tube 3 Tube 4 rubbed with sandpaper, and the other with ordinary paper. The one rubbed with sandpaper shines more than the other. Give a reason.
Answer:

While rubbing with sandpaper, more frictional force is produced between the layers of the metal sheet and sandpaper, which causes more force on the dust particles, and they are removed easily, so it will shine more. But in the case of ordinary paper, the force of friction is not sufficient to remove all the dust, so it will shine less in this case.

Question 5. Friction is In force that acts betweenn two surfaces that slide across one another. It is net in the opposite direction in which the object is moving. Friction is the cause of it both in and out. It prevents our shoes from slipping on the footpath when we walk, but sometimes it may also harm us. It reduces the efficiency of a machine. There isn’t a lot of energy loss due to friction. Friction enn bo produced by some methods. For example, we use lubricants like oil, grease to reduce the friction between the moving parts of n machine. In many machines, friction is reduced by using ball bearings.

1. Which of the following can be used as a lubricant?

1. Mustard oil
2. Soil
3. Paper
4. Iron powder

Answer: 1. Mustard oil

2. Friction always acts in which direction that to the moving body.

1. Perpendicular
2. Same direction
3. Opposite direction
4. Always downward

Answer: 3. Opposite direction

NCERT Class 8 Science Chapter 9 Friction LAQs

3. Friction can be increased by using

1. Lubricant
2. Chalk powder
3. Oil
4. Talcum powder

Answer: 2. Chalk powder

NCERT Solutions For Class 8 Science Chapter 7 Reaching The Age Of Adolescence LAQs

Question 1. Rohan and Seema were childhood friends. When Seema became eleven years old, her breasts started developing. Rohan’s voice became deeper, his shoulders and chest became wider.
Answer:

1. Give a word for the characteristics that are developed in Rohan and Seema.
Answer:

Both Rohnn and Seema have developed secondary sexual characteristics,

NCERT Class 8 Science Chapter 7 Reaching the Age of Adolescence LAQs

2. Name the hormone that is responsible for these sexual characteristics in Seema.
Answer:

Oestrogen is the hormone responsible for these sexual characteristics in Seema.

3. After a few years, Rohan observed a bulge in ills neck. What could be the possible reason for tills bulge in his neck?
Answer:

The bulge in Rohan’s neck is called Adam’s apple, which is formed because the male larynx grows bigger during puberty.

Question 2. Sanjay and Seoma were childhood friends. When Soenia became 12 years old, she developed a little swelling in her neck. She visited a doctor who prescribed some medicines and asked her to take an iodine-rich diet. After some time, she felt better. Later, her friend Sanjay also developed a little protrusion on his throat. He got worried. But when he went to the doctor, he assured him that it was normal. It was just the development of secondary sexual characteristics in him.
Answer:

1. Describe briefly the meaning of ‘secondary sexual characteristics’.
Answer:

The external characters that distinguish a male from a female are called secondary sexual characteristics. For example, the development of the breast in girls and the growth of moustaches in boys.

NCERT Solutions for Reaching the Age of Adolescence Chapter 7

2. Explain the change that Sanjay was experiencing.
Answer:

Sanjay was experiencing the enlargement of the voice box. The growing voice box in boys can be seen as a protruding part of the throat.

3. Recommend any two measures to Sanjay and Seema to maintain their reproductive health during adolescence.
Answer:

The measures that can be taken to maintain their reproductive health are as follows

1. Maintain personal hygiene
2. Take a balanced and nutritious diet

Question 3. When Sudlia reached a certain age tho vaginal bleeding started occurring after regular Interval of time. Her mother told her to take special care of her hygiene during this period.
Answer:

1. Name the process occurring after regular intervals.
Answer:

This process is known as menstruction

2. What does the onset of this process in females signify?
Answer:

The one set of menstruation signifies that the reproductive system of a female has started working

Class 8 Chapter 7 Reaching the Age of Adolescence Long Answer Questions

3. Give the reason why her mother told her to take special care of her hygiene during this period
Answer:

Her mother told her to take special care of her hygiene during this period because if it is maintained, there might be chances of not the occurrence of bacterial infections.

4. Shobha gave birth to a healthy baby girl. Her husband was unhappy with the news and held her responsible for the baby to do a girl. Was her husband just a flood of blaming her for the birth of a baby girl?
Answer:

No husband was not justified in blaming his Wife for the birth of a baby. As the unfertilized egg of a female always has one

1. Draw a diagram to show how the sex of a fetus is determined.
Answer:

Mother- XX Father – XY

Question 4. Observe the chart and graph given in the figure carefully and answer the following questions.

1. Which of the lines represents the height of boys?
2. Which line represents the height of girls?
3. What is the difference between the pattern of Increase in the height of boys and girls?
4. Is this pattern true for each individual?

Answer:

1. The dotted line represents the height of boys.
2. The solid line represents the height of girls.
3. At the onset of puberty, girls grow faster in height than boys, and by the age of 18 years, both reach their maximum height.
4. No, the rate of growth in height varies among individuals. Some may grow in height suddenly at puberty and then slow down, while others may grow gradually.

NCERT Solutions for LAQs on Reaching the Age of Adolescence

Question 5. Our government has legalised the age for marriage for boys and girls. Give reasons as to why one should get married after a certain age.
Answer:

In our country, the legal age for marriage is 18 years for girls and 21 years for boys. This is because teenage mothers are not prepared mentally or physically for motherhood.

Early marriage and motherhood cause health problems for both the mother and the child. It also curtails employment opportunities for the young woman and may cause mental agony as she is not ready to shoulder the responsibilities of motherhood.

Also, boys before that age may not be mentally mature and financially secure enough to take on the responsibilities of a family. Thus, one should get married only after a certain age.

NCERT Solutions For Class 8 Science Chapter 10 Sound: Very Short Answer Questions

Question 1. How is the blind folded person able to guess which player is nearer to her?
Answer: The vibration due to the movement of a closer player is more than others, and the blind folded person can easily imagine in which direction a player is nearer to her.

NCERT Solutions for Sound VSAQs Class 8

Question 2. Briefly mention the experience when you touch a sound-producing school bell.
Answer: When we touch a sound-producing school bell, we feel the vibration in it.

Question 3. How does the sound propagate?
Answer: Sound needs a medium for propagation.

Question 4. Is it possible that the decreasing amount of air in the tumbler had something to do with the decreasing loudness of the ring?
Answer: Yes, if the amount of air starts decreasing in the tumbler, then the loudness of the ring also decreases.

Question 5. Does sound travel in liquids?
Answer: Yes, sound can travel through liquids.

NCERT Solutions for Class 8 Science Sound VSAQs

Question 6. Can you say that sound can travel through strings?
Answer: Yes, Sound can travel through strings.

Question 7. How can we hear sound through solids, liquids, and gases?
Answer: Sound travels faster in solids compared to liquids and gases because the particles in solids are much closer together than in liquids and gases.

Question 8. If an object oscillates 20 times in 1s, what would be its frequency?
Answer: As we know, the frequency is the total number of oscillations in 1 s. So, the frequency will be 20 Hz.

Question 9. How is it possible that you can recognise many familiar sounds without seeing the objects producing them?
Answer: We can recognise many familiar sounds of objects without seeing them because different objects produce different sounds.

NCERT Solutions for Sound Chapter 10 VSAQs

Question 10. What factors make the sound differ from each
Answer: Amplitude and frequency

Question 11. Is there any difference between the sound of a baby and that of an adult?
Answer: Yes, the frequency of the sound of a child is higher than that of an adult.

Question 12. Why is your voice different from that of your teacher?
Answer: This is because of the sound.

Question 13. Can we hear the sound of all vibrating bodies?
Answer: A sound is audible to us only if the sound produced by the vibrating body is in the audible range, i.e., 20 Hz to 20 kHz.

Class 8 Science Chapter 10 Sound Very Short Answer Questions

Question 14. Is the sound always pleasing?
Answer: No

Question 15. Can you list some sources of noise pollution?
Answer: Sounds of vehicles, bursting crackers, loudspeakers, etc.

Question 16. Name the sources in the home that may lead to noise.
Answer: The sources that may lead to the noise are transistors, radio at high volume, television, desert coolers, air conditioners, etc.

Sound Class 8 VSAQs and Answers

Question 17. How can the noise pollution be controlled in a Residential area?
Answer: The following steps should be taken to control noise pollution in a residential area

1. The television and loudspeaker should be run at low volumes.
2. Silencing devices must be installed in the transport vehicles, like tractors, trucks, etc.
3. Industries should be set up away from the residential areas.

NCERT Solutions For Class 8 Science Chapter 7 Reaching The Age Of Adolescence SAQs

Question 1. Who should be involved Inking modelclnos/drug unions prescribed by n doctor? Give Ronsons.
Answer:

We should avoid hiking medications/drugs unless prescribed by a doctor because several medicines have adverse side effects and have specific dosage levels, which, if not followed, may harm the body. Drugs can be addictive too and can ruin our health and happiness.

Question 2. Given below are certain food Items required for proper nourishment of the child, cents. Name the nutrients present in the food Items and write their functions.
Answer:

Reaching the Age of Adolescence Class 8 SAQs

Question 3. Paheli and Boojho realised that a sudden increase in height and the hairy line above the lips in boys were signs of adolescence. They wanted to know about other changes at puberty.
Answer:

The other changes in the body are as follows

1. Change in body shape.
2. Increase in height.
3. Increased activity of sweat and sebaceous glands.

Question 4. Paheli and Boojho have now understood that puberty marks the beginning of the reproductive period when one becomes capable of reproduction. But they want to know if reproductive life once begins, it continues, or it ends sometime.
Answer:

The capacity for maturation and production of gametes lasts for a much longer time in males than in females. In females, the reproductive phase of life begins at puberty (10 to 12 years of age) and generally lasts till the age of approximately 45 to 50 years.

NCERT Solutions for Reaching the Age of Adolescence Chapter 7

Question 5. List changes in the body that take place at puberty.
Answer: At puberty, the body undergoes the following changes

• Bow and girls become capable of reproduction
• Sudden increase in height.
• Broad shoulders and wide chests in boys, and the region below the waist becomes wider in girls.
• Growth of hair on different parts of the body.
• The voice of girls becomes high-pitched, and that of boys becomes deep.
• Secretions of sweat and sebaceous glands increase.
• Sex organs become active. In boys, the testes start to form sperm, and in girls, the ovaries enlarge and eggs begin to mature.
• Changes at the mental, intellectual, and emotional level.

Reaching the Age of Adolescence Class 8 SAQs

Question 6. Prepare a table having two columns depicting the names of endocrine glands and the hormones secreted by them.
Answer:

The table is shown below.

Class 8 Chapter 7 Reaching the Age of Adolescence Short Answer Questions

Question 7. What are sex hormones? Why are they named so? State their functions.
Answer:

The hormones that are responsible for the male and female secondary sexual characteristics are called sex hormones.

They are called sex hormones as they control the sexual activities and help us to distinguish boys from girls. In boys, sex hormones control the formation of sperm by the testes and the growth of facial hair, etc., and in girls, they help to develop breasts, control the menstrual cycle, etc.

NCERT Class 8 Chapter 7 Reaching The Age Of Adolescence VSAQs

Question 1. XX or XY, state the combination of sex chromosomes that produces a male child?
Answer: XY combination of sex chromosomes produces a male child.

Question 2. The nucleus of a cell contains chromosomes for inheritance. How many chromosomes are there in the nuclei of a human cell?
Answer: The nucleus of each human cell contains 23 pairs of chromosomes.

Question 3. Name the endocrine gland attached to the base of the brain.
Answer: Pituitary gland.

Question 4. Name some endocrine glands other than the pituitary gland.
Answer: Some endocrine glands other than the pituitary are the thyroid, pancreas, and adrenals.

Class 8 Science Reaching the Age of Adolescence very short answer questions

Question 5.  Boojho begins wondering how long this period marked by changes in the body would last.
Answer: The period marked by change, i.e. adolescence, begins around the age of 11 and lasts upto 18 or 19 years of age.

Question 6. Paheli, on the other hand, is worried about this period of life when you are neither a child nor an adult. She wondered whether this period between childhood and adulthood had a special name.
Answer: The period oflife between childhood and adulthood is termed adolescence.

Question 7. Both Boojho and Paheli wish to know what initiates changes at puberty.
Answer: The changes that occur at adolescence are controlled by hormones.

NCERT Solutions for Reaching the Age of Adolescence Chapter 7

Question 8. Pahell heard her mother and her aunt talking about her cousin who is going to have a baby. They were discussing whether she would give birth to a boy or a girl. She wonders what makes the fertilised egg develop into either a boy or a girl.
Answer: Inside the fertilised egg or zygote is the instruction for determining the sex of the baby. This instruction is present in the thread-like structures called chromosomes.

Question 8. Are there hormones in other animals also? Do they have any role to play in reproduction?
Answer: Yes, animals also have hormonal secretions. Yes, hormones have their role to play in reproduction.

Question 9. If people do not have enough iodine in their diet, will they get goitre caused by lack of thyroxine?
Answer: Yes, if people do not have enough iodine in their diet, they will get goitre caused by lack of thyroxine

VSAQs for Reaching the Age of Adolescence Chapter 7 Class 8

Question 10. What is the term used for secretions of endocrine glands responsible for changes taking place in the body?
Answer: Hormone is the term used for secretions of endocrine glands responsible for changes taking place in the body.

Question 11. Define adolescence.
Answer: Adolescence is the period of life in which organisms become reproductively active. In other words, it is the period of attaining reproductive maturity in boys and girls, which starts from 11-13 years and lasts upto 18-19 years in humans.