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Class 8 Science Question Answers

Question Answer

Class 8

Science

Master Class 8 Science: Engagi...

Class 8 Science Question Answers

Which of the following departments prepare weather reports?A. Pollution department B .Health departmentC .Meteorological departmentD .Environment department

What is step farming?

Give full form of LPG and CNG.

Discovery of the nucleus of an atom was due to the experiment carried out by:A.BohrB.RutherfordC.MoseleyD.Thomson

Major consumer of wood from the forest is________________.A) Thermal power plantB) Paper industryC) Chemical industryD) None

Different species are classified into different threat categories in the_____A. Blue Data BookB. Yellow Data Book C. Black Data BookD. Red Data Book

Name the petroleum product for surfacing roads.

Why are we able to sip hot tea or milk faster from a saucer rather than a cup?

Which category of paper can be used for recycling?A. Mill brokeB. Pre-consumer wasteC. Post consumer wasteD. All of the Above

Define adolescence.

What is evaporation of Water?A.It is a process during which neither heat is absorbed nor evolvedB.It is a process accompanied by chemical reaction C.exothermic processD.endothermic process

The gas oil fraction of petroleum has the highest boiling point? A. TrueB. False

Which are mostly anaerobic?A. AlgaeB. MossesC. FungiD. All the above

Minamata disease is caused by pollution of water by:- A. Cadmium B. Mercury C. Lead D. Arsenic.

How do you appreciate the uses of cattle?

Name the first national park of the world. Write the name of the country in which it was established.

Which of the following statements is true about PVC (polyvinyl chloride) and polythene?A.They are thermoplasticsB.They are thermosetting plasticsC.They are examples of natural substancesD.They are natural fibres

Write the names of five things whose smell you like and five things whose smell you do not like.

A tadpole develops into an adult frog by the process of a. Fertilizationb. Metamorphosisc. Embeddingd. Budding

The poliovirus enters the human body througha. Mosquito biteb. Tick bitec. Saliva and secretions from the nosed. Contaminated food and water

Pebrine disease of silkworms is caused bya. Nosemab. Plasmodiumc. Dugesiad. Monocystis

What is a reversible process? What are its features?

The initial step for cultivation of crops isa. Sowingb. Preparation of soilc. Irrigationd. Harvesting

Identify the pollutant gases largely responsible for the discoloured and lusterless nature of marble of the Taj Mahal. A.CO2 and NO2 B.SO2 and NO2 C.O3 and CO2 D.SO2 and O3

How will you separate mango from a mixture of mango and apple?

The establishment of Taj Trapezium Zone (TTZ) enshrines which among the following objectives?A) Protection from PollutionB) Tourism DevelopmentC) Economy HubD) Transportation facilities

Write a note on the largest bird sanctuary of Asia.

A mixture of wheat grains and rice flakes can be separated by winnowing.A) TrueB) False

What is sowing?

The lowest temperature at which the substance starts burning is called_______.A. Minimum temperatureB. Maximum temperatureC. Boiling temperature D. Ignition temperature

Why do antibiotics kill bacteria but not viruses?A) Antibiotics stimulate the immune system against bacteria but not virusesB) Viruses have ways of blocking antibioticsC) Viruses are too small to be affected by antibioticsD) viruses do not have a metabolism

Plants which are very small and have soft stems such as grasses are called asA) ClimbersB) LianasC) OffsetD) Herbs

: What conditions are required for rusting to take place?A.Water onlyB.Oxygen onlyC.Water and oxygenD.Water and carbon dioxide

State the differences between manure and fertilizer.

List three differences between the artery and vein.

Which of the following is an example of non-biodegradable waste?A. FruitsB. VegetablesC. PaperD. Polythene

Which of the following is not a renewable source of energy?A. Hydrocarbon fuelB. Water energyC. Solar energyD. Wind energy

Water is liquid at room temperature. Which of the following is the correct reason to justify it? A. In water the intermolecular forces are strong enough to keep its particle-bound with each other. B. The melting point of water is below room temperature.C. Its boiling point is above room temperature. D. All of the above.

The ultimate energy source of all ecosystems is? (a) Producers(b) Organic molecules(c) Carbohydrates(d) Solar radiation

The cell organelle where photosynthesis occurs isA) ChlorophyllB) MesophyllC) ChloroplastD) Thylakoid

“Red rust of tea” is caused by parasitic(a)Algae(b)Fungi (c)Bacteria(d)Bryophyte

Mulching is a process that helps ina) Weed controlb) Soil fertilityc) Moisture conservationd) Improvement of soil structure

Write down an application of Radiocarbon.

Rahat system of irrigation isa. A large well in which rope and container is usedb. A large well in which wheel is usedc. A small well which is connected with pipesd. None of these

It is said the Taj Mahal may be destroyed due toA. Flood in Yamuna riverB. Decomposition of marble as a result of high temperatureC. Air pollutants released from oil refinery of MathuraD. All of the above

What is mycorrhiza? How does it help as biofertilizers?

Which of the following are the advantages of plastic over metals?1.Plastics are lighter.2.Plastics are usually cheaper.3.Plastics are inert to both acids and alkalis.(1) and (2) only(1) and (3) only(2) and (3) only(1) (2) and (3)

How is soil formed?

Which features adapt penguins to live in extremely cold conditions?A.A white colour thick skin and less fat B.Thin skin large eyes white fur C.White colour thick skin and lot of fatD.White body paws for swimming gills for respiration

______ supports combustion.A. Sodium bicarbonateB. HydrogenC. Carbon dioxideD. None of these

Distinguish between fats and oils.

Name five objects which can be made from wood.

A fungal disease that spreads by seeds and flowers is:a. Loose smut of wheatb. Corn smutc. Covered smut of barleyd. Soft rot of potato

The Indian wild ass (Asinus hemionus) is found in:(a)Garhwal Himalayas(b)Plateau of Ladakh(c)Thar desert(d)Rann of Kutch

The process of pasteurization was invented in….A. 1864B. 1964 C. 1867D. 1854

Petroleum plant isA) SugarcaneB) MaizeC) PotatoD) Euphorbia

The primary method of treatment of sewage water involves which of the following processes?(a) Sludge digestion(b) Aerobic bacterial activity (c) Anaerobic bacterial activity(d) Filtration and sedimentation\t

Choose the correct statement about inflammable substances from the following statements. They have:A) low ignition temperature and cannot catch fire easily.B) high ignition temperature and can catch fire easily.C) low ignition temperature and can catch fire easily.D) high ignition temperature and cannot catch fire easily.

Weeds affect the crop plants byA. Killing the crop plants before they growB. Secreting poisons which cause diseases in crop plantsC. Competing for various resources of crop plants causing low availability of nutrientsD. None of the above

Covered smut of Sorghum is caused by: a. Sphaelotheca cruentab. Sphaelotheca reilianac. Sphaelotheca sorghid. Tolyposporium ehrenbergii

What are the four sources of Surface Water?

What are the advantages of intercropping and crop rotation?

List four characteristics of a mixture.

A wholesale woolen fibre dealer gets the woolen fibre of different textures sorted for various purposes. Match the items in Column I with the woolen fibre in Column II.Column IColumn II(a) Pashmina Shawl(i) Camel wool(b) Woolen Carpet(ii) Angora wool(c) Baby blanket(iii) Kashmir goat(d) Woolen sweater (iv) Sheep wool

Micropyle of seed is involved in the passage ofa. Male Gameteb. Pollen Tubec. Waterd. Gases

Dry ammonia has no action on litmus paper but a solution of ammonia in water turns red litmus paper blue. Why?

Herbicides are chemicals which control-A) InsectsB) FungiC) WeedsD) Nematodes

Anaerobic fermentation is a process which helps in the formation of:A.coal gasB.natural gasC.water gasD.Petroleum

Which of the following is\/are non – biodegradable?A.TyreB.PlasticC.Electronic componentsD.All of the above

Powdery mildew of Pea is caused by:a. Pucciniab. Erysiphec. Ustilagod. Alternaria

Synthetic fibres are also called artificial or human-made fibres.(A) True(B) False

The increasing order of boiling points for the following compound is: A. C2H5OH B. C2H5Cl C. C2H5CH3 D. C2H5OCH3

Write the economic importance of rice.

Kanha national park is located in(a) Assam(b) Rajasthan(c) Uttar Pradesh(d) Madhya Pradesh

The organic manure is considered better than fertilisers becauseA.It can be prepared in the factoriesB.It is less rich in plant nutrientC.It improves the texture of the soilD.It decreases the water holding capacity of the soil

Black stem rust of Wheat is caused by:a. Fungusb. Protozoac. Algad. Bacterium

The presence of a particular group of bacteria in water bodies indicates contamination. Identify the group.

What is meant by leaching?

Write any three differences between manure and fertilizer.

What is the difference between plasma semi-liquid state molten state?

How bacteria are useful in industry? Write any two uses?

What are fabrics?

Herpetophobia is the fear ofA)SnakesB)RatsC)WaterD)All of the above

Management of forest and wildlife resources is a very challenging task. Why? Give any two reasons.

Which of the following is NOT a food crop?A. MaizeB. BajraC. PaddyD. WheatE. Cotton

Groundnut is native ofA. BrazilB. IndiaC. JapanD. Philippines

Yarn is spun thread used for sewing weaving or knitting.A.True B.False

Aquatic animals use_____dissolved in water to respire. A. CO2 B. H2 C. O2 D. H2O2

The method of sowing seeds of tomato is:A. DrillB. BroadcastingC. TransplantationD. None of the above

What is spinning?

: What conditions are required for rusting to take place?A.Water onlyB.Oxygen onlyC.Water and oxygenD.Water and carbon dioxide

Wheat flour can be separated from the wheat bran by:A.) hand pickingB.) sieving C.) winnowingD.) filtration

We should not add wastes containing salts pickles oil vinegar meat and milk products in the vermicomposting pit to feed the redworms. Why?

The substance which is expected to have highest ignition temperature out of the following is ______________:A.CoalB.KeroseneC.PetrolD.Alcohol

Shruti has come to her ancestral village after an interval of ten years. She could not notice any garbage dumps on the roadsides. Surprised on reaching her residence she asked her grandmother as to where the garbage dumps went?

What is the lower layer of the atmosphere called?A) ionosphereB) MesosphereC) TroposphereD) Stratosphere

The main function of a cultivator is(A)To turn the soil(B)To make a furrow in the soil(C)To pulverize the soil(D)All of the above functions

The young unopened flower is termed as______.

Why should a magnesium ribbon be cleaned before burning in air?

Identify I, Il, and III in the given flow chart and select the correct option. A. I-Biosphere reserve, II-Gene Bank, III- cryopreservation B. I-Gene Bank, Il-Wildlife sanctuary III-Home gardens C. I-Biosphere reserve, II-National park, III-Wildlife sanctuary D. I-cryopreservation, Il-Biosphere reserve, Ill- National park