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CBSE Class 8 Science Chapter 7 Reaching The Age Of Adolescence Activitys

Activity 1

Aim: To determine the maximum height that would be reached at the end of the growth period.

Materials Required: Graph paper, pencil, table, etc

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Procedure:

1. Use the data given in the table in the previous activity to draw a graph.
2. Take age as an X X-axis and per cent growth in height on the Y-axis.
3. Mark the point representing your age on the graph (Let the age of a girl be 11 years, height be 120 cm).
4. Find out the percentage of height already reached and calculate the height she might eventually reach

Observation

At the age of 11 years (girl), the point of age touches the 88% mark on the height axis. So, the maximum height that will eventually be reached

Present height / % of full height at this age x = 100 = 136.36 cm

Conclusion: From this activity, we conclude that we can determine the maximum height that would be reached at the end growth period using the formula.

CBSE Class 8 Science Chapter 4 Combustion And Flame Activity Ideas Activity 1

Aim: To show that the quality of the burning flame depends on the amount ofair available around it.

Materials Required: A candle, a glass chimney, a few wooden blocks and a glass plate.

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Procedure:

• Fix a lit candle on a table.
• Put a glass chimney on the candle.
• Rest this arrangement of the chimney on the wooden blocks.
• Make sure that air can enter the chimney
• Remove the wooden blocks and let the chimney rest on the table.
• Finally, put a glass plate over the chimney
• Note the observations.

Observation: When the chimney is on wooden blocks, the candle burns freely as the air enters the chimney. When the wooden blocks are removed, the air does not enter the chimney.

Due to this, the candle starts to produce smoke. You will also observe the flame of a candle flickering. Now, when we put the glass plate over the chimney, the flame finally goes.

Conclusion: We can conclude that air is necessary for burning. Partial availability ofair causes the smoke to be produced. Complete lack ofair causes the flame to go off.

Class 8 Science Chapter 4 Combustion And Flame Hands-On Experiments Activity 2

Aim: To show the supply of oil needed for combustion.

Materials Required: A Piece of wood or charcoal, an Iron plate or tawa, a glass jar or a transparent plastic jar.

Procedure:

1. Place a piece of burning wood or charcoal on the Iron plate or tawa.
2. Cover it with the glass jar or the transparent plastic jar.
3. Note the observation.

Observation: Wood or charcoal burns under the jar and continues burning for some time. But, after some time burning stops.

Conclusion: Wood and charcoal stop burning after they are covered with a glass or transparent plastic jar, which shows that air is necessary for combustion.

CBSE Class 8 Science Chapter 4 Combustion And Flame Simple Experiments Activity 3

Aim: To show that ignition temperature is essential for substances like paper to burn.

Materials Required: A Sheet of paper, water and candles.

Procedure:

1. Make two paper cups by folding a sheet of paper.
2. Pour about 50 ml of water into one of the cups.
3. Heat the cups separately with the help of a candle.
4. Note your observations.

Observation: We see that the empty paper cup catches fire easily and starts burning. On the other hand, the paper cup containing water does not catch fire. The water in the cup becomes hot gradually. If continued heating, water will start even boil in the paper cup.

Conclusion:

• When we heat an empty paper cup, its ignition temperature is reached quickly. It catches fire and starts burning.
• When we heat the paper cup having water, the heat is transferred to the water by conduction. The Ignition temperature of paper is not reached, and hence, it does not burn.
• This shows that ignition temperature is essential for a substance to burn.

Class 8 Science Chapter 4 Combustion and Flame Activity With Step-By-Step Guide Activity 4

Aim: To show that the innermost zone of a candle flame consists of unburnt wax vapour.

Materials Required: A candle, a glass tube, a pair of tongs and a matchstick.

Procedure:

1. Light the candle carefully.
2. Hold the glass tube with a pair of tongs.
3. Introduce one end of the glass tube in the dark zone of a non-flickering candle flame.
4. Bring the lit matchstick near the other end of the glass tube as shown in the figure given above.

Note your observations.

Observation: When a lit matchstick is brought near the other end ofthe glass tube, we observe a flame at this end. It is because the innermost zone (dark zone) of the candle flame consists of unburnt wax vapours. Some vapours from it enter the glass tube. When the lit matchstick is brought near it, the wax vapours start burning and produce a flame.

Conclusion: A flame burns at the other end of the glass tube when a matchstick is lit near it. Hence, we can conclude that the innermost zone (dark zone) candle flame has unburnt wax vapours.

Activity 5

Aim: To show that the middle zone of a candle flame consists of unburnt carbon particles.

Materials Required: A candle, a glass plate, and a pair of tongs.

Procedure:

1. Light the candle.
2. Hold the glass plate with a pair of tongs as shown in the figure.
3. Introduce the glass plate in the middle zone.
4. Hold it for 10 seconds and then remove.

Note the observation.

Observation: When the glass plate is kept over the middle zone of the flame, a blackish circular ring is formed. The blackish ring is produced due to the deposition of unburnt carbon particles present in the luminous zone of the flame.

Conclusion: The observation concludes that the partial combustion of wax vapours in the luminous zone produced unburnt carbon particles.

CBSE Class 8 Science Chapter 4 Combustion And Flame Activity With Observation Notes Activity 6

Aim: To show that the outermost zone of a flame is the hottest

Materials Required: A copper wire, a pair of tongs and a candle.

Procedure:

1. Take a copper wire.
2. Hold it’s one end with a pair of tongs.
3. Introduce its other end just inside the flame (outermost zone) for about 30 seconds.

Note the observation.

Observation: We observe that the portion of the copper wire just inside the flame gets red hot.

Conclusion: The observation concludes that the outermost, non-luminous zone of the flame has a high temperature. Hence, it is the hottest part of the flame.

CBSE Class 8 Science Chapter 4 Combustion and Flame worksheet With Answers Fill In The Blanks

Question 1. A __________ process in which a substance reacts with _____ to give off heat is called combustion.
Answer: chemical, oxygen

Question 2. When the clothes of a person catch __________, the person is covered with a __________ to extinguish the fire.
Answer: Fire, blanket

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Question 3. The substances that give very __________ ignition temperatures and can easily catch fire with a flame are called __________ substances.
Answer: Low, inflammable

Question 4. The substances which vaporise during _____________ given flame.
Answer: Burning

Question 5. Wood, paper, and CNG are substances.
Answer: Combustible

Question 6. Burning of wood and coal causes _______ of air.
Answer: Pollution

Question 7. A liquid fuel used in homes is ________.
Answer: Kerosene

question 8. Fuel must be heated to its _______ before it starts burning.
Answer: Ignition temperature

Question 9. Fire produced by oil cannot be controlled by ________.
Answer: Water

Question 10. ___________ fuel is cheap, readily available, and causes less
Answer: Ideal

Question 11. ___________ gas is a promoter of combustion
Answer: Oxygen

CBSE Class 8 Science Chapter 4 Extra Questions And Answers For Exam Preparation: True or False

Question 1. Air is necessary for combustion.
Answer: True

Question 2. Magnesium is a non-combustible metal.
Answer: False, magnesium is a combustible metal.

Question 3. Carbon dioxide is an excellent fire extinguisher.
Answer: True

Question 4. Water is the best extinguisher for fires involving electrical equipment.
Answer: False, carbon dioxide is the best extinguisher for fires involving electrical equipment.

Question 5. The middle zone is the hottest zone of a flame.
Answer: False, the outer zone is the hottest zone of a flame.

Question 6. LPG fire is an inflammable substance.
Answer: True

Question 7. Spontaneous combustion takes place in the absence of external heat.
Answer: True

CBSE Class 8 Science Chapter 4 Combustion And Flame Match The Columns

Question 1. Match Column 1 with Column 2.

Answer: A—4, B—6, C—5, D—3, E—1, F—2

Question 2. Match the following for the flame of a candle

Answer: A-3—x, B-2—z, C-l—y

Question 8. Match Column 1 with Column 2.

Answer: A-3, B-1. C-4, D-2

CBSE Class 8 Science Chapter 4 Combustion and Flame

The following questions consist of two statements: Assertion (A) and Reason (R). Answer these questions by selecting the appropriate option given below.

1. Both A and R are true, and R is the correct explanation of A
2. Both A and R are true, but R is not the correct explanation of A
3. A is true, but R is false
4. A is false, but R is true

Question 9.

1. Assertion (A): Electrical components can catch fire.
2. Reason (R) Electrical fire can be extinguished using water.

Answer: 3. A is true, but R is false

Question 10.

1. Assertion (A) A Candle can burn a block of wood.
2. Reason (R) The Ignition temperature of wood is high.

Answer: 4. A is true, but R is false

The following questions consist of two statements. Assertion (A) and Reason (R). Answer the following questions by selecting the appropriate options given below.

1. Both A and R are true, and R is the correct explanation of A.
2. Both A and R are true, but R is not the correct explanation of A.
3. A is true, but R is false.
4. A is false, but R is true.

Question 1.

Assertion (A) Fireworks produce different colours.
Reason (R) Different chemicals are used in the fireworks to produce different colours.

Answer: 1. Both A and R are true, and R is the correct explanation of A.

Question 2.

Assertion (A) Spontaneous combustion can occur in materials like dry leaves.
Reason(R) Spontaneous combustion happens due to the presence of excess oxygen in materials.

Answer: 3. A is true, but R is false. R can be corrected as Spontaneous combustion occurs in materials that have a low ignition temperature. Through internal chemical reaction with oxygen, they release heat and burn on their own.

Question 3.

Assertion (A) LPG gas can catch fire easily.
Reason (R) LPG has a high ignition temperature.

Answer: 3. A is true, but R is false. R can be corrected as LPG has a low ignition temperature, so it catches fire easily.

Question 4.

Assertion (A) When a burning candle is covered with a glass jar, the flame goes out.
Reason (R) The glass jar prevents the flow of oxygen to the candle flame.

Answer: 1. Both A and R are true, and R is the correct explanation of A.

CBSE Class 8 Chapter 5 Conservation of Plants And Animals MCQs With Answers PDF Review Exercise Multiple Choice Questions

Question 1. There is a list of some events.

1. Tilting of soil for sowing seeds on a deserted land.
2. Cutting down trees to make tables and chairs.
3. Establishing a forest on land that had trees before.
4. Clearing forests for building houses.

Deforestation will be caused by which of the following events?

1. 1 and 2
2. 3 and 1
3. 2 and 4
4. 2 and 3

Answer: 3. 2 and 4

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Question 2. How is a decline in trees connected to a water shortage?

1. Deforestation increases Earth’s temperature, resulting in less rainfall
2. Deforestation decreases Earth’s temperature, which reduces the moisture content of the air
3. Deforestation disturbs the soil composition, leading to high water retention by the soil
4. Deforestation prevents the absorption of water by the plants, reducing the groundwater level

Answer: 1. Deforestation increases Earth’s temperature, resulting in less rainfall

Question 3. Deforestation increases the level of one of the following in the atmosphere.

1. Ozone
2. Carbon dioxide
3. Oxygen
4. Water vapour

Answer: 2. Carbon dioxide

Question 4. In our country, large patches of forests are being cleared for the cultivation of crops. The environmental impact of such a practice will lead to

1. Soil erosion
2. Soil pollution
3. Soil conservation
4. Soil fertility

Answer: 1. Soil erosion

Question 5. The amount of soil erosion is lower in areas with more trees. How do trees stop the Earth from eroding?

1. The roots of the trees hold die top layer of the soil firmly
2. The trees absorb more sunlight, which increases soil density
3. The trees store extra food in the soil, which increases the soil content
4. The trees add dead leaves to the soil, which increases the soil.

Answer: 1. The roots of the trees hold die top layer of the soil firmly

Question 6. Which one of the following changes may occur due to desertification?

1. A decrease in atmospheric temperature
2. Increase in water holding capacity of soil
3. Increased chances of floods
4. Conversion of fertile land into a desert

Answer: 4. Conversion of fertile land into a desert.

Question 7. Cutting down trees and clearing forests are common construction methods for industries. What is its potential impact on nature?

1. A decrease in the number of wildlife
2. Sudden boost in the plant growth
3. Availability of more food for wildlife
4. Increase in the percentage of land occupied by trees

Answer: 1. Decrease in the number of wildlife

Question 8. Which one of the following statements is true about a biosphere reserve?

1. It is a protected area where only endemic species live
2. It is meant only for the conservation of plants and animals
3. It is meant to conserve both the biodiversity and the culture of that area
4. There are no other protected areas within its limits

Answer: 3. It is meant to conserve both the biodiversity and the culture of that area

Question 9. Radha went for a trip to a Pachmarhi Biosphere Reserve in Madhya Pradesh and Jim Corbett National Park in Uttarakhand. Which common activity is likely to be observed in both the protective areas?

1. Both provide a protective environment for fauna only
2. Both provide shelter to humans as well as wildlife
3. Both allow human activities for interaction with wild animals
4. Neither interferes with the natural environment of the wildlife

Answer: 4. Both do not interfere with the natural environment of the wildlife

Question 10. The place of living of an organism in the environment is called

1. Home
2. Habitat
3. Resort
4. Reservoir

Answer: 3. Resort

Class 8 Science Most Important Mcqs From The Conservation Chapter

Question 11. What do the black buck, elephant, python, and golden cat together represent in a forest?

1. Fauna
2. Flora
3. Ecosystem
4. Species

Answer: 1. Fauna

Question 12. Them Is n list of some organisms.

1. Star fish
2. Cheetah
3. Fern
4. Shrub
5. Cactus
6. Wolf

Which choice properly categorises the flora and fauna?

Answer: 2.

Question 13. Which one of the following statements is true about endemic species?

1. They are found exclusively in a specific habitat
2. Endemic species can never become endangered
3. They are found only in zoos and botanical gardens
4. They are not affected by the destruction of their habitat

Answer: 1. They are found exclusively in a specific habitat

Question 14. Satpura National Park and Bori sanctuary are present in the Pachmarhi Biosphere Reserve. How do these regions contribute to the protection of wildlife and plants?

1. These large areas provide artifical habitat to wildlife
2. These large areas conserve organisms and their habitats
3. These large areas control the number of wildlife by preventing natural breeding
4. These large areas prevent the interaction of organisms with wildlife to keep them safe

Answer: 2. These large areas conserve organisms and their habitats

CBSE Class 8 Science Chapter 5 Conservation of Plants And Animals Important Questions With Answers Long Answer Questions

Question 1. Is deforestation associated with global warming? Explain.
Answer: Trees (and other plants) use carbon dioxide gas from the atmosphere for the process of food making called photosynthesis. When a lot of trees are cut down during deforestation, then lesser number of trees will be left. The lesser number of trees will use up less carbon dioxide, due to which the amount of carbon dioxide in the atmosphere will still increase. In this way. Deforestation increases the level of carbon dioxide in the atmosphere. Carbon dioxide gas traps the sun’s heat rays reflected by the Earth (causing the greenhouse effect). Trapping of heat rays by carbon dioxide increases the temperature of Earth’s atmosphere. This will lead to global warming. The gradual increase in the overall temperature of Earth’s atmosphere due tothe greenhouse effect caused by the increased level of carbon dioxide in the atmosphere is called global warming.

Question 2. How does deforestation lead to frequent floods and droughts?
Answer: When the forest trees are cut down, the number of trees decreases, which results in less transpiration. Reduced transpiration causes a decrease in the amount of water vapour in the atmosphere, resulting in less rainfall.

When there is less rainfall in an area, then less water percolates into the ground. Due to this, the groundwater level also gets lowered. The shortage of surface water (in ponds, lakes, etc.) and groundwater due to persistent low rainfall in an area can lead to droughts.

Deforestation also leads to a decrease in the water-holding capacity of the soil. The movement of water from the soil surface into the ground is reduced. So, there are floods.

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Question 3. Which of these are the effects of deforestation? Circle ‘Yes’ or ‘No’ for the correct response.

Answer: Yes, No, Yes

CBSE Class 8 Science Chapter 5 Conservation Of Plants Very Short Answer Questions

Question 1. Arrange the following to show how deforestation leads to water pollution.

1. The roots of the trees no longer have a firm grip on the soil.
2. Rain falls onto the ground.
3. The trees of a forest are cut down.
4. The loose soil gets washed away into a nearby body of water.

Answer: 3-1-2-4

Question 2. A gas is utilised by the trees and plants in photosynthesis. The same gas also traps the heat rays reflected by the Earth, and is also given out by humans during respiration. Name the gas and the phenomenon of an increase in temperature for which it is responsible.
Answer: The gas is carbon dioxide, and the phenomenon is global warming.

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Question 3. Why is it important to conserve forests?
Answer: Forest conservation maintains the balance in nature. It acts as a carbon sinks absorbing CO 2 and keeps global warming at bay.

Question 4. Mention any one action that you have undertaken to conserve trees.
Answer: I have planted some trees a nd look after them carefully so that they are well protected. This is the action I have taken to conserve trees.

Question 5. ‘Variety of all forms of life found in a region’ is known by a specific name; what is it?
Answer: Biodiversity.

Question 6. Name the protected area built to support biodiversity.
Answer: A Biosphere reserve supports biodiversity.

Question 7. Out of the three biosphere reserves, a National park or a wildlife sanctuary, which is the largest?
Answer: Biosphere reserve is the largest of the three, and it may contain a National park or a wildlife sanctuary.

Question 8. Endemic fauna is restricted to a particular area. Name a few in India.
Answer: Bison and flying squirrel are endemic fauna of Pachmarhi Biosphere Reserve in India.

Question 9. What is the unique feature of the biodiversity found in the Pachmarhi Biosphere Reserve?
Answer: The biodiversity found in Pachmarhi Biosphere Reserve is similar to that of the upper Himalayan peaks and to those belonging to the Western Ghats.

Question 10. How are even small animals important in an ecosystem?
Answer: Small animals might be small in size, but their role in the ecosystem cannot be ignored. They are important in an ecosystem as they form part of food chains and food webs.

Question 11. A group of cats is found in a forest that interbreed freely. What is the term used for them?
Answer: A species is a group of the same kind of organisms that can interbreed to produce fertile offspring.

Question 12. Name the plant found in Satpura forests.
Answer: The finest Indian teak is found in the Satpura forests.

Question 13. Name the first reserve forest of India.
Answer: Satpura National Park is the first reserve forest of India.

Question 14. Mention the aim of the Forest (Conservation) Act.
Answer: The aim of the Forest (Conservation) Act is the preservation and conservation of natural forests and meeting the basic needs of the people living in or near the forests.

CBSE Class 8 Science Chapter 5 Conservation Of Plants Short Answer Questions

Question 1. We have often read in the newspaper about the careful use of natural resources. What is the term used for it? Mention some of the Earth’s natural resources that need to be used carefully.
Answer: ‘Conservation’ is a term used to describe the prudent (careful and sensible) use of natural resources. The Earth’s natural resources that need to be conserved are air, water, soil, minerals, fuels, plants, and animals.

Question 2. Soil erosion and desertification are the consequences of deforestation. Justify.
Answer: Deforestation causes soil erosion, i.e., removal of the top layer ofsoil. It also changes the physical properties of soil. Thus, exposing the lower, hard, and rocky layers of soil that have less humus and are less fertile. Gradually, the fertile land gets converted into deserts. This is called desertification.

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Question 3. A new species X is introduced into a forest. How is it likely to affect the local species of that area?
Answer: The new species is likely to affect the local species as it poses threats in the following manner

1. Preying on native species.
2. Out-competing for food or other resources.
3. Causing or carrying a disease.
4. Preventing native species from reproducing.
5. Changing food webs.

Question 4. Sometimes, animals enter human habitation, killing people and causing damage to materials. Why do the animals behave like this?

Answer: Animal behaviour can be understood from the explanation given below

As human populations expand into wild animal habitats, their territory is displaced. Reduction in the availability of food sources forces the animal to seek alternate sources. Thus, drawing them towards human habitation.

Question 5. Roshni attended a seminar on forest and Wildlife conservation. She, on returning home, discussed it with her brother. If she had given some measures, she would have mentioned conserving forests and wildlife.

Answer: Forests and wildlife can be conserved by following

Protection by law. It is very necessary to have strict laws and their enforcement for the protection and preservation of wildlife, for Example, hunting regulations.

Reforestation is the act of planting more trees to replace the ones that are cut.

Habitat preservation. In this method, protected areas such as Wildlife sanctuaries, National parks, Biosphere reserves, etc., are established. These areas are large enough to protect the diverse and whole set of ecosystems

Question 6. Why are endemic organisms in greater danger of becoming extinct?
Answer: Endemic organisms are confined to a limited geographical area. They cannot adapt to or live outside their natural habitat; any disturbance to their habitat will adversely affect them. Thus, they are in greater danger of becoming extinct.

Question 7. Why are wildlife sanctuaries important for the conservation of plants and animals?
Answer: In a wildlife sanctuary, killing and capturing wild animals are strictly prohibited. It does not allow any human activity that disturbs the wild animals or their habitat. So, in these areas, animals live in a natural environment, protected from people. This is why sanctuaries are important.

Question 8. Recycling and the saving of paper are related to deforestation. Justify.
Answer: Trees are used in making paper. About 17 fully grown trees are used to make one tonne of paper. So, the wastage of paper is also a cause of deforestation. Therefore, we should recycle and save paper. If we save paper, we can save many trees in a year. In this way, recycling and the saving of paper are directly related to deforestation.

Question 9. Boojho wonders if there is a record of the endangered species.
Answer: The Red Data Book is the source book that keeps a record of all endangered animals and plants.

Question 10. Paheli is curious to know what would happen if we had no wood? Is there any alternative available for wood? Boojho says that paper is one of the important products we get from forests. Boojho asks whether there are any alternatives available for paper
Answer: Without wood, we would not have access to fuel and many other household necessities like paper, matchsticks, furniture, etc. The use of digital technology could replace paper.

CBSE Class 8 Science Chapter 5 Conservation Of Plants Fill In The Blanks

Question 1. A place where animals are protected in their natural habitat is called a _____.
Answer: Wildlife sanctuary

Question 2. Species found only in a particular area are known as ________.
Answer: endemic species

Question 3. Migratory birds fly to faraway places because of __________ changes.
Answer: climatic

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Question 4. __________ traps the heat of the Sun’s rays.
Answer: Carbon dioxide

Question 5. Conversion of fertile land into a desert is called __________
Answer: Desertification

Question 6. Pachmarhi is an example of __________.
Answer: Biosphere reserve

Question 7. Plants found in a particular area are termed as __________.
Answer: flora

Question 8. A group of populations that are capable of interbreeding is called a __________.
Answer: Species

Question 9._________ is an example of the endemic flora of the Pachmarhi Biosphere Reserve.
Answer: Salt

Question 10. _________ is the first reserve forest of India.
Answer: Satpura National Park

CBSE Class 8 Science Chapter 5 Conservation Of Plants True or False

Question 1. Green plants utilise oxygen to prepare food through photosynthesis.
Answer: False

Question 2. Endemic species are those that are exclusively found in a particular area.
Answer: True

CBSE Class 8 Science Chapter 5 Conservation Of Plants Match The Columns

Question 1. Match Column 1 with Column 2

Answer: A- 4, B-3, C-5, 0-2, H- 1

Question 10. Match Column 1 with Column 2

Answer: A-3, B-1 C-4, D-2

CBSE Class 8 Science Chapter 5 Conservation Of Plants

The following question consists of two statements: Assertion (A) and Reason (R). Answer these questions by selecting the appropriate options given below.

1. Both A and R are true, and R is the correct explanation of A
2. Both A and R are true, but R is not the correct explanation of A
3. A is true, but R is false
4. A is false, but R is true

Question 1.

Assertion (A) Deforestation leads to drought.
Reason (R) The consequent increase in temperature on the Earth disturbs the water cycle. This leads to a decrease in rainfall.

Answer: 1. Both A and R are true, and R is the correct explanation of A.

Question 2.

Assertion (A): Conserving biodiversity is a necessity.
Reason (R): Biodiversity is a part of the web of life, and its loss can affect other species and ecosystems.

Answer: 1. Both A and R are true, and R is the correct explanation of A.

Question 3.

Assertion (A): Bison is an example of endemic fauna.
Reason (R): Endemic species are those species that no longer exist anywhere on Earth.

Answer: 3. A is true, but R is false. R can be corrected as the endemic species are those species of plants and animals that are found exclusively in a particular area. For example, bison is an endemic fauna of the Pachmarhi biosphere reserve.

Question 4.

Assertion (A): Members of a species have common characteristics.
Reason (R): Species is a group of populations that are not capable of interbreeding.

Answer: 3. A is true, but R is false. R can be corrected as a Species is a group of populations that are capable of interbreeding.

Question 5.

Assertion (A) Project Tiger was launched by the government of the United States.
Reason (R) It was launched to ensure the survival and maintenance of the tiger population in the country.

Answer: 4. A is false, but R is true. R can be corrected as ‘Project Tiger’ was launched by the government of India.

The following questions consist of two statements: Assertion (A) and Reason (R). Answer these questions by selecting the appropriate option given below.

1. Both A and R are true, and R is the correct explanation of A.
2. Both A and R are true, but R is not the correct explanation of A.
3. A is true, but R is false.
4. A is false, but R is true.

Question 11.

Assertion (A): Wildlife sanctuary, National park, and Biosphere reserve are protected areas.
Reason (R): In these areas, plantation cultivation, grazing, felling trees, hunting, and poaching are prohibited.

Answer: 1. Both A and R are true, and R is the correct explanation of A.

Question 12.

1. Assertion (A): Rock shelters are found inside the Satpura National Park.
2. Reason (R) A total of 55 rock shelters have been identified in the Pachmarhi Biosphere Reserve.

Answer: 2. Both A and R are true, but R is not the correct explanation of A.

CBSE Class 8 Science Chapter 6 Reproduction In Animals Multiple Choice Questions

Question 1. Which of the following is not a part of the human male reproductive system?

1. Testes
2. Oviducts
3. Seminal vesicles
4. Epididymis

Answer: 2. Oviducts

Question 2. Sets of reproductive terms are given below. Choose the set that has an Incorrect combination

1. Sperm, testis, sperm duct, penis
2. Menstruation, egg, oviduct, uterus
3. Sperm, oviduct, egg, uterus
4. Ovulation, egg, oviduct, uterus

Answer: 3. Sperm, oviduct, egg, uterus

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Question 3. Which of the following statements about reproduction in humans is correct?

1. Fertilisation takes place externally
2. Fertilisation takes place in the testes
3. During fertilisation, the egg moves towards the sperm
4. Fertilisation takes place in the human female

Answer: 4. Fertilisation takes place in the human female

Question 4. A stage of sexual reproduction is represented below. Select the correct statement describing the process shown in the image

1. Several ova penetrate the egg cell and fertilise it to form a zygote
2. Several sperm penetrate the egg cell and fertilise it to form a zygote
3. A single ova penetrates the egg cell and fertilises it to form a zygote
4. A single sperm penetrates the egg cell and fertilises it to form a zygote

Answer: 4. A single sperm penetrates the egg cell and fertilises it to form a zygote

Question 5. After fertilisation, the resulting cell, which gives rise to a new individual, is the

1. Embryo
2. Ovum
3. Foetus
4. Zygote

Answer: 4. Zygote

Question 6. Which of these animals reproduces by external fertilisation?

1. Snake
2. Frog
3. Horse
4. Elephant

Answer: 2. Frog

Question 7. Internal fertilisation occurs

1. Inside the male body
2. Outside the male body
3. Inside the female body
4. Outside the female body

Answer: 3. Inside the female body

Question 8. Where doos tho fertilisation of oggs occur In the process of In Vitro Fertilisation (IVF)?

1. Ovary
2. Wate
3. Uterus
4. Petri dish

Answer: 4. Petri dish

Question 9. In human beings, the correct sequence of events

1. Gamete formation, fertilisation, zygote formation embryo
2. Embryo, zygote formation, fertilisation, gamete formation
3. Fertilisation, gamete formation, embryo, zygote formation
4. Gamete formation, fertilisation, embryo, zygote formation

Answer: 1. gamete formation, fertilisation, zygote formation, embryo

Question 10. Animals exhibiting external fertilisation produce a large number of gametes. Pick the appropriate reason

1. The animals are small in size and want to produce more offspring
2. Food is available in plenty of water
3. To ensure a better chance of fertilisation
4. Water promotes the production of a large number of gametes

Answer: 3. To ensure a better chance of fertilisation

Question 11. In human beings, after fertilisation, the structure which gets embedded in the wall of the uterus is

1. Ovum
2. Embryo
3. Foetus
4. Zygote

Answer: 2. Embryo

Question 12. In humans, the development of a fertilised egg takes place in the

1. Ovary
2. Testis
3. Oviduct
4. Uterus

Answer: 4. Uterus

Question 13. Which table given below correctly represents the classification of the animals into viviparous and oviparous animals?

CBSE Difference Between Sexual And Sexual Reproduction Class 8 Notes Long Answer Questions

Question 1. After observing the figure below, answer the following.

Read the following statements and label them in the figure.

1. The part that produces female gametes.
Answer: Ovary (produces gametes)

2. The tire part where the development of the baby takes place.
Answer: Uterus (development of body takes place

3. The part through which the developing embryo passes to reach the uterus.
Answer: Oviduct (Fallopian tube through which the embryo reaches the uterus)

Questions 2. Explain the future development of the embryo that would take place after it gets embedded in the uterus.
Answer: The embryo continues to develop after it gets embedded into the uterus. It divides and differentiates into three germ layers, which give rise to different body parts such as hands, legs, head, eyes, ears, etc.

His stage where all the body parts are distinct and easily identified in a developing embryo is called the foetus. After the completion of the development of the foetus, the mother gives birth to the baby.

Question 3. Consider the diagram below and answer the following question.

1. A mature egg and a sperm unite to form a zygote. In which part of the female reproductive system does a zygote form?

1. 1
2. 2
3. 3
4. 4

Answer: 1. 1

2. How many ova are usually released each month by the ovary of a woman?

1. One
2. Two
3. Fourteen
4. Twenty-four

Answer: 1. One

Read And Learn More CBSE Class 8 Science Long Answer Questions

3. In which part of the female reproductive system does an embryo implant?

1. 1
2. 2
3. 3
4. 4

Answer: 2. 2

Question 4. Which of these statements is true about a foetus? Circle ‘Yes’ or No for the correct response

Answer:

1. Yes
2. No
3. No

Question 5. The table shows the processes of external fertilisation and internal fertilisation

Which of these is true about external fertilisation and internal Fertilisation?

Answer: Both parents are necessary.

Question 6. The picture shows the life cycle of a moth. What can be concluded from the picture? Circle ‘Yes’ or ‘No’ for the correct response.

Answer:

1. Yes
2. Yes
3. No

Question 7. The pictures show three types of reproduction in animals

Which of those statements is true?

• Type 1 reproduction is called binary fission
• Type 2 reproduction produces two non-identical offspring.
• Type 3 reproduction involves unequal distribution of genetic materials.
• Types 1, 2, and 3 reproduction methods involve a single parent only.

Answer: 2. Type 1, 2, and 3 reproduction methods involve a single parent only.

The following questions consist of two statements:

Assertion (A) and Reason (R). Answer these questions by selecting the appropriate option given below.

1. Both A and R are true, and R is the correct explanation of A
2. Both A and R are true, but R is not the correct explanation of A
3. A is true, but R is false
4. A is false, but R is true

Answer: 10. A-3, B-l.C-4, D-2

Question 8.

Assertion (A) During metamorphosis tadpole is transformed into a caterpillar.
Reason (R) Metamorphosis is a process in which a larva is transformed into an adult

Answer: 1. Both A and R are true, and R is the correct explanation of A

Question 9.

Assertion (A) Cloning of an animal was successfully performed for the first time by Ian Wilmut and his colleagues.
Reason (R) Cloning is the production of a different copy of a cell or any living part or a complete organism

Answer: 3. A is true, but R is false