Chapter 1 Nutrition in Plants
Q1 :Why do organisms need to take food?
Answer :
All living organisms require food to survive. It gives them energy to perform various activities. All activities such as playing, running, walking, studying, etc. Require energy. The various components present in our food such as carbohydrates, proteins, fats, vitamins, and minerals provide energy to our body. These are also important for growth and development of the body.
Q2 :Distinguish between a parasite and a saprotroph.
Answer :
Parasite
The organism that grows on the body of another organism and derives nutrients from it is known as a parasite.
Examples of parasites are Cuscuta and orchids.
Saprotroph
The organism that obtains nutrients from the dead or decaying organic matter is known as saprotroph.
Examples of saprotrophs are fungi and some bacteria.
Q3 :How would you test the presence of starch in leaves?
Answer :
Experiment to test the presence of starch in leaves:
Take two healthy green potted plants of the same type. Keep one potted plant in a dark room for one or two days in order to remove all the starch from the leaves. Keep the other plant in sunlight. Now, take one leaf from each potted plant and put a few drops of iodine solution on them. Then note down the observation.
Plants kept in light and dark conditions
No blue black colour will be observed on the leaves of the plant kept in the dark room. This indicates the absence of starch. Blue
black colour will be observed on the leaves of the plant kept in sunlight. This indicates the presence of starch.
Q4 :Give a brief description of the process of synthesis of food in green plants.
Answer :
Photosynthesis is defined as the process in which the chlorophyll-containing plant cells synthesise food in the form of carbohydrates, using carbon dioxide and water in the presence of solar energy.
materials required for photosynthesis:
(a) Water is taken in from the roots of the plant and is transported to the leaves.
(b) Carbon dioxide from the air enters the leaves through the tiny pores called stomata
(c) Solar energy is used to break water into hydrogen and oxygen. This hydrogen is combined with carbon dioxide to form food for the plants, which is ultimately used by the animals as well.
Q5 :Show with the help of a sketch that the plants are the ultimate source of food.
Answer :self
Q6 :Fill in the blanks:
Answer :
(a) Green plants are called __autotrophs__ since they synthesise their own food.
(b) The food synthesised by the plants is stored as __starch__.
(c) In photosynthesis solar energy is captured by the pigment called chlorophyll__.
(d) During photosynthesis plants take in __carbon dioxide__ and release __oxygen__.
Q7 :Name the following:
(i) A parasitic plant with yellow, slender and tubular stem.
(ii) A plant that has both autotrophic and heterotrophic mode of nutrition.
(iii) The pores through which leaves exchange gases.
Answer :
(i) Cuscuta
(ii) Pitcher plant
(iii) Stomata
Q10 :Mark 'T' if the statement is true and 'F' if it is false:
Answer :
(i) Carbon dioxide is released during photosynthesis. (F)
(ii) Plants which synthesise their food themselves are called saprotrophs. (F)
(iii) The product of photosynthesis is not a protein. (T)
(iv) Solar energy is converted into chemical energy during photosynthesis. (T)
Q11 :Choose the correct option from the following:
Which part of the plant takes in carbon dioxide from the air for photosynthesis?
(i) Root hair
(ii) Stomata
(iii) Leaf veins
(iv) Sepals
Answer :(ii) Stomata
Q12 :Choose the correct option from the following:
Plants take carbon dioxide from the atmosphere mainly through their:
(i) roots
(ii) stem
(iii) flowers
(iv) leaves
Answer : (iv) leaves
Chapter 2 Nutrition in Animals
Exercise Solutions
Q1 :Fill in the blanks:
Answer :
(a) The main steps of nutrition in humans are __ingestion__, __digestion__, __absorption__, __assimilation__ and__egestion__.
(b) The largest gland in the human body is __liver__.
(c) The stomach releases hydrochloric acid and __digestive__ juices which act on food.
(d) The inner wall of the small intestine has many finger-like outgrowths called __villi__.
(e) Amoeba digests its food in the _food vacuole_.
Q2 :Mark 'T' if the statement is true and 'F' if it is false:
Answer :
(a) Digestion of starch starts in the stomach. (F)
(b) The tongue helps in mixing food with saliva. (T)
(c) The gall bladder temporarily stores bile. (T)
(d) The ruminants bring back swallowed grass into their mouth and chew it for some time. (T)
Q3 :Tick mark the correct answer in each of the following:
Answer :
(a) Fat is completely digested in the
(i) stomach (ii) mouth
(iii) small intestine (iv) large intestine
(b) Water from the undigested food is absorbed mainly in the
(i) stomach (ii) food pipe
(iii)small intestine (iv) large intestine
Q4 :Match the items of Column I with those given in Column II:
Answer :
Column I Column II
Food components Product(s) of digestion
Carbohydrates Sugar
Proteins Amino acids
Fats Fatty acids and glycerol
Q5 :What are villi? What is their location and function?
Answer :
Villi are tiny finger-like projections originating from the walls of the small intestine. They increase the surface area for absorption of the digested food. The blood vessels present inside the villi can absorb the nutrients from the digested food.
Q6 :Where is the bile produced? Which component of the food does it help to digest?
Answer :
Liver secretes the bile juice which is stored in the gall bladder. Bile plays an important role in the digestion of fats.
Q7 :Name the type of carbohydrate that can be digested by ruminants but not by humans. Give the reason also.
Answer :
Cellulose is a type of carbohydrate that can be digested by ruminants and not by humans. Ruminants have a large sac-like structure between small and large intestine where the food containing cellulose is digested by the action of certain bacteria. On the other hand, humans cannot digest cellulose, as the cellulose digesting enzymes are absent in them.
Q8 :Why do we get instant energy from glucose?
Answer :
Glucose is a simple sugar. Carbohydrates, when consumed, have to be digested into glucose. As glucose can be easily absorbed in
blood, it provides energy to the body. Hence, when glucose is directly taken, it does not have to be digested and thus acts as an instant source of energy.
Q9 :Which part of the digestive canal is involved in:
Answer :
(i) absorption of food __small intestine__
(ii) chewing of food __buccal cavity__
(iii) killing of bacteria __stomach__
(iv) complete digestion of food __small intestine__
(v) formation of faeces __large intestine__
Q10 :Write one similarity and one difference between the nutrition in Amoeba and human beings.
Answer :
Similarity between nutrition in Amoeba and human beings:
Both Amoeba and humans require energy for the growth and maintenance of their bodies. This energy is derived from the food that they eat. The food that they consume is always in a complex form and is therefore broken down into simpler forms by the process of digestion. Hence, both these organisms are heterotrophs.
Differences between nutrition in Amoeba and human beings:
Digestion in Humans Digestion in Amoeba
(i) Humans have a mouth and a complex (i) Mouth and digestive system are digestive system. absent in Amoeba.
(ii) Digestive juices are secreted in the buccal (ii) Digestive juices are secreted in cavity, stomach, and small intestine. the food vacuole.
(iii) Digestion of carbohydrates, proteins, and fats (iii) All the food components are starts in separate regions. digested in the food vacuole.
Q11 :Label the following figure of the digestive system.
Answer :see NCERT text book figure
Q12 :Can we survive only on raw, leafy vegetables/grass? Discuss.
Answer :No.
Humans cannot survive only on raw, leafy vegetables, or grass. It is because the grass is rich in cellulose, which is a type of
carbohydrate that humans are not able to digest due to the absence of cellulose-digesting enzymes.
Chapter 3 Fibre to Fabric Exercise Solutions
Exercise :
Q1 :You must be familiar with the following nursery rhymes:
(i) 'Baa baa black sheep, have you any wool.'
(ii)'Mary had a little lamb, whose fleece was white as snow.' Answer
the following:
(a) Which parts of the black sheep have wool?
(b) What is meant by the white fleece of the lamb?
Answer :
(a) Wool is obtained from the hairy fibres (hair) of the sheep.
(b) White fleece of the lamb refers to the white coloured hair of the lamb.
Q2 :The silkworm is (a) a caterpillar, (b) a larva. Choose the correct option.
(i) a (ii) b (iii) both a and b (iv) neither a nor b
Answer :(iii) both a and b
Q3 :Which of the following does not yield wool?
(i) Yak (ii) Camel (iii) Goat (iv) Woolly dog
Answer :(iv)Woolly dog
Q4 :What is meant by the following terms?
(i) Rearing (ii) Shearing (iii) Sericulture
Answer :
(i) Rearing: Rearing means helping someone to grow up.
(ii)Shearing: It is the process of removal of fleece along with a thin layer of skin from the body of sheep.
(ii) Sericulture: Sericulture refers to the rearing of silkworms to obtain silk.
Q5 :Given below is a sequence of steps in the processing of wool. Which are the missing steps? Add them.
Shearing, __________, sorting, __________, __________, __________
Answer :
Shearing, __scouring__, sorting, __picking of burrs__, __dying of fibres__, making of yarn__
Q6 :Make sketches of the two stages in the life history of the silk moth which are directly related to the production of silk.
Answer :
The two stages in the life history of silk moth directly related to silk production are ......(draw figure from text book)
Q7 :Out of the following, which are the two terms related to silk production?
Sericulture, floriculture, moriculture, apiculture and silviculture
Hints: (i) Silk production involves cultivation of mulberry leaves and rearing silkworms.
(ii) Scientific name of mulberry is Morus alba.
Answer :Sericulture and moriculture
Q8 :Match the words of Column I with those given in Column II:
Answer :
Column I Column II
(i) Scouring (e) Cleaning sheared skin
(ii) Mulberry leaves (c) Food of silk worm
(iii) Yak (b) Wool yielding animal
(iv) Cocoon (a) Yields silk fibres
Q9 :Given below is a crossword puzzle based on this lesson. Use hints to fill in the blank spaces with letters that complete thewords.
Down Across
(D) 1: Thorough washing (A) 1: Keeps warm
2: Animal fibre 2: Its leaves are eaten by silkworms
3: Long thread like structure 3: Hatches from egg of moth
Chapter 4 Heat
Exercise :
Q1 :State similarities and differences between the laboratory thermometer and the clinical thermometer.
Answer :
Similarities:
(i) Both clinical and laboratory thermometers have long, narrow, uniform glass tubes.
(ii) The bulbs of both the thermometers have mercury in them.
Differences:
(i) The temperature range of clinical thermometers is from 35°C to 42°C while that of laboratory thermometer is from -10°C to
110°C.
(ii) Clinical thermometer is used to measure the temperature of a human body. However, laboratory thermometer cannot be used
to measure the temperature of a human body.
(iii) The least count of both the thermometers differs.
(iv) Unlike clinical thermometer that can be tilted, laboratory thermometer is kept upright while reading the temperature values.
Q2 :Give two examples each of conductors and insulators of heat.
Answer :Two examples of conductors of heatare:
(i) Aluminium
(ii) Iron
Two examples of insulators of heat are:
(i) Wood
(ii) Plastic
Q3 :Fill in the blanks:
(a) The hotness of an object is determined by its __ __.
(b)Temperature of boiling water cannot be measured by a ____ thermometer.
(c) Temperature is measured in degree ___ _.
(d) No medium is required for transfer of heat by the process of ___ _.
(e) A cold steel spoon is dipped in a cup of hot milk. It transfers heat to its other end by the process of __ _ _.
(f) Clothes of ___ _ colours absorb heat better than clothes of light colours.
Answer :
(a) The hotness of an object is determined by its __temperature__.
(b) Temperature of boiling water cannot be measured by a __clinical__thermometer.
(c) Temperature is measured in degree __Celsius__.
(d) No medium is required for transfer of heat by the process of __radiation __.
(e) A cold steel spoon is dipped in a cup of hot milk. It transfers heat to its other end by the process of __conduction__.
(f) Clothes of __dark__colours absorb heat better than clothes of light colours.
Q4 Match the following:
(i) Land breeze blows during (a) summer
(ii) Sea breeze blows during (b) winter
(iii) Dark coloured clothes are preferred during (c) day
(iv) Light coloured clothes are preferred during
Answer :
(i) Land breeze blows during (d) night
(ii) Sea breeze blows during (c) day
(iii) Dark coloured clothes are preferred during (b) winter
(iv) Light coloured clothes are preferred during (a) summer
Q5 :Discuss why wearing more layers of clothing during winters keeps us warmer than wearing just one thick piece of
clothing.
Answer :During winters, we prefer wearing more layers of clothing than just one thick piece of clothing because air gets trapped in between the various clothing layers. Being a poor conductor of heat, air prevents heat loss from our body. Hence, layers of clothing keep us warmer than a single layer.
Q6 :Look at Figure. Mark where the heat is being transferred by conduction, by convection and by radiation.
Answer :
(i) Transfer of heat from burner to pan is by radiation.
(ii) Transfer of heat from pan to water is by conduction.
(iii) Transfer of heat within water is by convection.
Q7 :In places of hot climate it is advised that the outer walls of houses be painted white. Explain.
Answer :In places of hot climate, it is advised to paint the outer walls of houses as white because a light colour such as white reflects back most of the heat that falls on it. Hence, a light colour tends to keep the house cool.
Q8 :One litre of water at 30°C is mixed with one litre of water at 50°C. The temperature of the mixture will be
(a) 80°C (b) more than 50°C but less than 80°C
(c) 20°C (d) between 30°C and 50°C
Answer :
(d) The temperature of the mixture will be between 30°C and 50°C.
Q9 :An iron ball at 40°C is dropped in a mug containing water at 40°C.
The heat will
(a) flow from iron ball to water.
(b) not flow from iron ball to water or from water to iron ball.
(c) flow from water to iron ball.
(d) increase the temperature of both.
Answer :
(b) The heat will not flow from iron ball to water or from water to iron ball as both the substances have same temperature.
Q10 :A wooden spoon is dipped in a cup of ice cream. Its other end
(a) becomes cold by the process of conduction.
(b) becomes cold by the process of convection.
(c) becomes cold by the process of radiation.
(d) does not become cold.
Answer :(d) Its other end does not become cold as wood is a bad conductor of heat.
Q11 Stainless steel pans are usually provided with copper bottoms. The reason for this could be that (a)
copper bottom makes the pan more durable.
(b) such pans appear colourful.
(c) copper is a better conductor of heat than the stainless steel.
(d) copper is easier to clean than the stainless steel.
Answer :
(c) The reason for this is that copper is a better conductor of heat than stainless steel.
Chapter 6 Physical and Chemical Changes
Exercise Solutions
Q1 :Classify the changes involved in the following processes as physical or chemical changes:
(a) Photosynthesis
(b) Dissolving sugar in water
(c) Burning of coal
(d) Melting of wax
(e) Beating aluminium to make aluminium foil
(f) Digestion of food
Answer :
(a) Photosynthesis → Chemical change
(b) Dissolving sugar in water → Physical change
(c) Burning of coal → Chemical change
(d) Melting of wax → Physical change
(e) Beating aluminium to make aluminium foil → Physical change
(f) Digestion of food → Chemical change
Q2 :State whether the following statements are true or false. In case a statement is false, write the corrected statement in your notebook.
(a) Cutting a log of wood into pieces is a chemical change. (True/False)
(b) Formation of manure from leaves is a physical change. (True/ False)
(c) Iron pipes coated with zinc do not get rusted easily. (True/False)
(d) Iron and rust are the same substances. (True/False)
(e) Condensation of steam is not a chemical change. (True/False)
Answer :
(a) False
Cutting a log of wood into pieces is a physical change.
(b) False
Formation of manure from leaves is a chemical change.
(c) True, it is a chemical change
(d) False, Iron and rust are different substances. Rust is iron oxide
(e) True
Q3 :Fill in the blanks in the following statements:
(a) When carbon dioxide is passed through lime water, it turns milky due to the formation of _________.
(b) The chemical name of baking soda is _________.
(c) Two methods by which rusting of iron can be prevented are _________and ____ ____.
(d) Changes in which only _____ __ properties of a substance change are called physical changes.
(e) Changes in which new substances are formed are called _________changes.
Answer :
(a) When carbon dioxide is passed through limewater, it turns milky due to the formation of __calcium carbonate (CaCO3).......
(b) The chemical name of baking soda is __sodium hydrogen carbonate__.
(c) Two methods by which rusting of iron can be prevented are __ galvanization __and __ painting__.
(d) Changes in which only __physical__properties of a substance change, are called physical changes.
(e) Changes in which new substances are formed are called __chemical __changes.
Q4 :When baking soda is mixed with lemon juice, bubbles are formed with the evolution of a gas. What type of change is it? Explain.
Answer :
When baking soda (Sodium hydrogen carbonate) is mixed with lemon juice (citric acid), bubbles are formed. The bubbles are formed due to the evolution of carbon dioxide gas. This is a chemical change. In this change, citric acid contained in lemon juice reacts with sodium hydrogen carbonate which results in the evolution of carbon dioxide gas.
Lemon juice( Citric acid) + Baking soda (Sodium hydrogen carbonate) → Carbon dioxide + Other substances
Q5 :When a candle burns, both physical and chemical changes take place. Identify these changes. Give another example of a familiar process in which both the chemical and physical changes take place.
Answer :
When a candle burns, both physical and chemical changes take place.
Physical change → Melting of wax
Chemical change → Burning of wax
Eating of food is another example where both physical and chemical changes occur simultaneously.
Physical change → Breaking down of larger food particles into smaller particles
Chemical change → Digestion of food
Q6 :How would you show that setting of curd is a chemical change?
Answer :
Once the curd is formed, milk cannot be re-obtained from it. Also, both milk and curd have different properties. Since these are the properties of a chemical change, setting of curd is a chemical change.
Q7 :Explain why burning of wood and cutting it into small piece are considered as two different types of changes.
Answer :
When we burn wood, a new substance, coal, is formed. Therefore, it is a chemical change. However, when we cut wood, only the shape and size of the wood are changed. No new substance is formed. Therefore, it is a physical change.
Q8 :Describe how crystals of copper sulphate are prepared.
Answer :
Crystals of copper sulphate are prepared by the method of crystallization. The process is as follows. A cupful of water is taken in a beaker. Few drops of dilute sulphuric acid are added to this. The water is then heated and when it starts boiling, copper sulphate
powder is added with stirring. Copper sulphate powder should be added on till the solution becomes saturated. It is then filtered into a china dish and allowed to cool. The solution should be kept undisturbed. Slowly, the crystals of copper sulphate separate out.
Q9 :Explain how painting of an iron gate prevents it from rusting.
Answer :
Rusting is aided by both moisture (water) and air (oxygen). By painting an iron gate, we prevent its contact from the air and moisture
present in the atmosphere. Hence, rusting is prevented.
Q10 Anaerobic bacteria digest animal waste and produce biogas (Change - A). The biogas is then burnt as fuel (Change - B). The following statements pertain to these changes. Choose the correct one.
(i) Process - A is a chemical change.
(ii) Process - B is a chemical change.
(iii) Both processes A and B are chemical changes.
(iv) None of these processes is a chemical change.
Answer (iii)
Chapter 7
Weather, Climate and Adaptations of Animals to Climate
Exercise
Q1 Name the elements that determine the weather of a place.
Answer :The elements that determine the weather of a place are temperature, humidity, rainfall, and wind speed.
Q2 When are the maximum and minimum temperatures likely to occur during the day?
Answer : The maximum temperature of the day occurs in the afternoon while the minimum temperature occurs early in the morning.
Q3 Fill in the blanks:
Answer :
(i) The average weather taken over a long time is called __climate__.
(ii) A place receives very little rainfall and the temperature is high throughout the year, the climate of that place will be__hot__and _ _dry__.
(iii) The two regions of the earth with extreme climatic conditions are _the polar region__ and _the tropical region__.
Q4 Indicate the type of climate of the following areas:
Answer :
(a) Jammu and Kashmir: __Moderately hot and wet__
(b) Kerala: __Hot and wet__
(c) Rajasthan: __Hot and dry__
(d) North-east India: __Wet__
Q5 Which of the two changes frequently, weather or climate?
Answer : Weather changes frequently.
Q6 Following are some of the characteristics of animals:
(i) Diets heavy on fruits (ii) White fur
(iii) Need to migrate (iv) Loud voice
(v) Sticky pads on feet (vi) Layer of fat under skin
(vii) Wide and large paws (viii) Bright colours
(ix) Strong tails (x) Long and large beak
For each characteristic indicate whether it is adaptation for tropical rainforests or polar regions. Do you think that some of these characteristics can be adapted for both regions?
Answer :
(i) Diets heavy on fruits → Tropical rainforests
(ii) White fur → Polar regions
(iii) Need to migrate → Polar regions
(iv) Loud voice → Tropical rainforests
(v) Sticky pads on feet → Tropical rainforests
(vi) Layer of fat under skin → Polar regions
(vii) Wide and large paws → Polar regions
(viii) Bright colours → Tropical rainforests
(ix) Strong tails → Tropical rainforests
(x) Long and large beak → Tropical rainforests
No
Q7 The tropical rainforest has a large population of animals. Explain why it is so.
Answer :
Theclimate of tropical rainforests is generally hot and humid with continuous rain. These hospitable climatic conditions support huge populations of plants and animals.
Q8 Explain, with examples, why we find animals of certain kind living in particular climatic conditions.
Answer : Certain kind of animals can be found in particular climatic conditions as they can adapt well to those conditions.
For example, a polar bear is adapted for polar regions. It has a thick skin and a layer of fat to keep it warm in cold conditions. However, with these adaptations, it will not be possible for it to survive in tropical region where it is hot.
Similarly, a monkey is adapted to live in the forests with features such as long and sturdy tail, loud voice, etc. These features are of no importance in polar regions where vegetation is very less. Therefore, certain types of animals live only in certain climatic conditions.
Q9 How do elephant living in the tropical rainforest adapt itself.
Answer : An important and widely found animal of Indian tropical rainforests is the elephant. It has adapted remarkably to the conditions of this region. Some of the adaptations are as follows.
(i) It uses its trunk as nose so that it has a strong sense of smell.
(ii) Its trunk is also used for picking up food.
(iii) Its tusks are used to tear bark of trees. It can eat barks of trees.
(iv) The soles of their feet are covered with thick pads. These pads can handle their enormous weight. They also prevent sound so that the elephants can move silently.
(v) Its large ears have strong sense of hearing.
Q10 Choose the correct option which answers the following question:
A carnivore with stripes on its body moves very fast while catching its prey. It is likely to be found in
(i) polar regions
(ii) deserts
(iii) oceans
(iv) tropical rainforests
Answer :
(iv) tropical rainforests
Q11 Which features adapt polar bears to livein extremely cold climate?
(i) A white fur, fat below skin, keen sense of smell.
(ii) Thin skin, large eyes, a white fur.
(iii) A long tail, strong claws, white large paws.
(iv) White body, paws for swimming, gills for respiration.
Answer :
(i)A white fur, fat below skin, keen sense of smell
Q12 Which option best describes a tropical region?
(i) hot and humid
(ii) moderate temperature, heavy rainfall
(iii) cold and humid
(iv) hot and dry
Answer :(i) hot and humid
Chapter 8 Wind Storms and Cyclotrons
Exercise
Q1 :Fill the missing word in the blank spaces in the following statements:
Answer :
(a) Wind is __moving__ air.
(b) Winds are generated due to __uneven__ heating on the earth.
(c) Near the earth's surface __warm__ air rises up whereas __cold__ air comes down.
(d) Air moves from a region of __high__pressure to a region of __low__pressure.
Q2 :Suggest two methods to find out wind direction at a given place.
Answer : The following are the two methods to find out the direction of wind.
(i) While flying a kite, air exerts pressure on the kite due to which the kite flies. The direction in which the kite flies is the direction of blowing of wind.
(ii) While riding a bicycle, the direction in which it is difficult to ride is opposite to the direction of the blowing wind.
Q3 State two experiences that made you think that air exerts pressure (other than those given in the text).
Answer :We have experienced that when we blow a balloon, the balloon becomes tight. If we try to fill more air, then the balloon will burst. This happens because air exerts pressure.
We have also experienced the movement windows and doors of our houses when wind blows in a high speed. This also happens because air exerts pressure.
Q4 You want to buy a house. Would you like to buy a house having windows but no ventilators? Explain your answer.
Answer : A house having windows but no ventilators should not be bought. This is because warm air is lighter than cold air and therefore, it goes up. This warm air can go outside the house through ventilators.
Q5 Explain why holes are made in hanging banners and hoardings.
Answer : Air exerts pressure. Wind blowing in high speed may break or displace many things. If holes are made in hanging banners and hoardings, then air can pass through these holes, which reduces the air pressure exerted on the banners and hoardings.
Q6 How will you help your neighbours in case cyclone approaches your village/town?
Answer In case cyclone approaches, the neighbours should be helped in the following ways.
(i) By helping in moving to cyclone shelters and other safer places.
(ii) By asking them to take necessary steps to shift animals, vehicles and household goods to safer places.
(iii) By calling the emergency services such as police, fire brigade and medical centres when required.
Q7 What planning is required in advance to deal with the situation created by a cyclone?
Answer :
The following planning is required to deal with the situation created by a cyclone.
(i) Facilities for cyclone prediction and forecasting which can give cyclone warning in advance.
(ii) Quick information and communication linkages so that information can be spread quickly.
(iii) Construction of cyclone shelters and arrangement for moving people to safer places for safety during cyclone.
Q8 Which of the following places is unlikely to be affected by a cyclone?
(i) Chennai (ii) Mangaluru (Mangalore)
(iii) Amritsar (iv) Puri
Answer : (iii) Amritsar
Q9 : Which of the statements given below is correct?
(i) In winter the winds flow from the land to the ocean.
(ii) In summer the winds flow from the land towards the ocean.
(iii) A cyclone is formed by a very high-pressure system with very high-speed winds revolving around it.
(iv) The coastline of India is not vulnerable to cyclones.
Answer :
(i) Correct
In winter the winds flow from the land to the ocean.This is called land breeze.
(ii) Not Correct
In summer the winds flow from the ocean towards the land. This is called sea breeze.
(iii) Not Correct
A cyclone is formed by a very low-pressure system with very high-speed winds revolving around it. The low-pressure region is called the eye of the cyclone.
(iv) Not Correct
The coastline of India is very vulnerable to cyclones.
Chapter 9 Soil
Exercise
Q1 : Tick the most suitable answer in question 1 and 2.
In addition to the rock particles, the soil contains
(i) air and water
(ii) water and plants
(iii) minerals, organic matter, air and water
(iv) water, air and plants
Answer : (iii)
Q2 : The water holding capacity is the highest in
(i) sandy soil
(ii) clayey soil (TRUE)
(iii) loamy soil
(iv) mixture of sand and loam
Qn3:
Column I Column II
(i) A home for living
organisms (b) All kinds of soil
(ii) Upper layer of the soil (c) Dark in colour
(iii) Sandy soil (a) Large particles
(iv) Middle layer of the soil (e) Lesser amount of humus
(v) Clayey soil (d) Small particles and packed tight
Q4 : Explain how soil is formed.
Answer :
Soil is formed through the process of weathering. Weathering is a process of physical breakdown and chemical decomposition of rocks and minerals near or at the surface of the earth. This physical and chemical decomposition is primarily done by wind, water, and climate. As a result of these processes, large rock pieces are converted into smaller pieces and eventually to soil.
Q5 : How is clayey soil useful for crops?
Answer :
Due to the very small size of the particles of clayey soil, particles are packed tightly and therefore can retain water. Clayey soil is also rich in organic matter. For growing crops such as wheat, gram, and paddy, the soil that is good at retaining water and rich in organic matter is suitable. Therefore, clayey soils having these characteristics are useful for such kind of crops.
Q6 : List the differences between clayey soil and sandy soil.
Answer :
Clayey soil
Sandy soil
1. The proportion of fine particles is higher. 1. The proportion of large particles is higher.
2. Particles are packed tightly.
2. Particles are loosely packed.
3. It can hold good amount of water.
3. It's ability to retain water is low.
4. Water cannot drain quickly.
4. Water can drain quickly.
5. It is heavy in weight.
5. It is light in weight.
6. Less air is trapped between the particles. 6. More air is trapped between the particles.
7. It is rich in humus.
7. It is not rich in humus.
Qn7: Answer
see figure in Ncert
Q8 : Razia conducted an experiment in the field related to the rate of percolation. She observed that it took 40 min for 200 mL of
water to percolate through the soil sample. Calculate the rate of percolation.
Answer :
Given amount of water = 200 mL
Percolation time = 40 min
Percolation rate=(amount of water 200 mL)/ (Percolation time 40 min)
= 5g/ml
Qn8:
Answer
1wind 2 erosion 3 wheat 4 sandy 5 profile polythene 6 clay 7 earthworm
Q10 : Explain how soil pollution and soil erosion could be prevented.
Answer :
Prevention of soil pollution:
The persistent build-up of toxic compounds in the soil is defined as soil pollution. To prevent soil pollution, its causes must be
controlled.
(i) Plastics and polythene bags destroy the fertility of soil. Hence, they should be disposed properly and if possible, their use should be avoided.
(ii) Some waste products from industries and homes pollute soil. These pollutants should be treated chemically to make them harmless before they are disposed.
(iii) Other pollutants of soil include pesticides and insecticides. Therefore, excessive use of these substances should be avoided.
Prevention of soil erosion:
Removal of the upper fertile layer of the soil (top soil) by strong wind and flowing water is known as soil erosion. Roots of plants bind the soil firmly and prevent soil erosion. Absence of plants leads to soil erosion. Therefore, soil erosion can be prevented by planting trees and checking indiscriminate cutting of trees.
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