Science: Class 7th: Chapter 8: Wins, Storms, and Cyclones

Question 1:

Fill the missing word in the blank spaces in the following statements:

(a) Wind is——————air.

(b) Winds are generated due to——————heating on the earth.

(c) Near the earth’s surface __________air rises up whereas ___________ air comes down.

(d) Air moves from a region of ——— pressure to a region of——— pressure.

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 air pressure to a region of low air pressure.

Question 2:

Suggest two methods to find out wind direction at a given place.

Answer:

Methods to finding out the wind direction at a given place are as follows

i. By seeing the direction of dry leaves released in the air.

ii By seeing the direction in which it is difficult to ride the bicycle.

Question 3:

State two experiences that made you think that air exerts pressure (other than those given in the text).

Answer:

i. When we fill the air in the balloon, it becomes tight and if we try to fill more air the balloon will burst which proves air exerts pressure.

ii. Wind causes curtains, doors and windows to move with the direction of the wind. This demonstrates air exerts pressure.

Question 4:

You want to buy a house. Would you like to buy a house having windows but no ventilators? Explain your answer.

Answer:

It is not a good idea to buy a house without ventilators because warm air is lighter than cold air hence warm air passes out of your home through ventilators. Accordingly, without ventilators, warm air will not pass out, and the house will remain warm.

Question 5:

Explain why holes are made in hanging banners and hoardings.

Answer:

Holes in the banners and hoardings help air to pass through it. Hence banners can withstand the pressure of the air and hence remain intact.

Question 6:

How will you help your neighbours in case a cyclone approaches your village/town?

Answer:

We can help our neighbours in case a cyclone approaches, by any of the following measures:

  • By helping them shift to a safer place.
  • By helping them to shift their animals, necessary households and vehicles to a safer place.
  • By calling emergency services such as fire station, police and medical centres.

Question 7:

What planning is required in advance to deal with the situation created by a cyclone?

Answer:

  • We should not ignore the warnings issued by the meteorological department through TV, radio, or newspapers.
  • We should — make necessary arrangements to shift the essential household goods, domestic animals and vehicles, etc. to safer places;
  • Avoid driving on roads through standing water, as floods may have damaged the roads.
  • Phone numbers of all emergency services like police, fire brigade, and medical centres should be handy.
  • Always store drinking water for emergencies.
  • Do not touch wet switches and fallen power lines.
  • Do not pressurise the rescue force by making undue demands.
  • Cooperate and help your neighbours and friends.

Question 8:

Which one of the following places is unlikely to be affected by a cyclone.

(i) Chennai

(ii) Mangaluru (Mangalore)

(iii) Amritsar

(iv) Puri

Answer:

(iii) Amritsar because Amritsar is far away from the sea while the remaining three are coastal areas and are likely to be hit by cyclones.

Question 9:

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) In winter, the winds flow from the land to the ocean.

Science: Class 7th: Chapter 7 Weather, Climate and Adaptations of Animals to Climate

Question 1:

Name the elements that determine the weather of a place.

Answer:

Temperature, humidity, rainfall and wind are the elements that determine the weather of a place.

Question 2:

When are the maximum and minimum temperatures likely to occur during the day?

Answer:

Maximum temperature occurs during day time, afternoon to be precise whereas minimum temperature occurs early in the morning.

Question 3:

Fill in the blanks:

(i) The average weather taken over a long time is called ___________.

(ii) A place receives very little rainfall and the temperature is high throughout the year, the climate of that place will be ___________ and ___________ .

(iii) The two regions of the earth with extreme climatic conditions are ___________ and __________.

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 polar region and tropical region.

Question 4:

Indicate the type of climate of the following areas:

(a) Jammu and Kashmir: _________________________________

(b) Kerala: ____________________________________________

(c) Rajasthan: __________________________________________

(d) North-east India: _____________________________________

Answer:

(a) Jammu and Kashmir: moderately hot and wet

(b) Kerala: hot and wet

(c) Rajasthan: hot and dry

(d) North-east India: wet

Question 5:

Which of the two changes frequently, weather or climate?

Answer:

Weather changes frequently but not climate

Question 6:

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 rain forests

(ii) White fur – Polar regions

(iii) Need to migrate – Polar regions

(iv) Loud voice – Tropical rain forests

(v) Sticky pads on feet – Tropical rain forests

(vi) The layer of fat under skin – Polar regions

(vii) Wide and large paws – Polar regions

(viii) Bright colours  – Tropical rain forests

(ix) Strong tails – Tropical rain forests

(x) Long and large beak – Tropical rain forests

Question 7:

The tropical rainforest has a large population of animals. Explain why it is so.

Answer:

Hot and humid temperature and continuous rainfall in the tropical rainforest suit the survival of many animals; hence, the tropical rainforest has a large population of animals.

Question 8:

Explain, with examples, why we find animals of a certain kind living in particular climatic conditions.

Answer:

Animals are adapted to survive in the conditions in which they live. Animals living in very cold and hot climates must possess special features to protect themselves against the extreme cold or heat.

Example: Polar bears have white fur so that they are not easily visible in the snowy white background. It protects them from their predators. It also helps them in catching their prey. To protect them from extreme cold, they have two thick layers of fur. They also have a layer of fat under their skin. In fact, they are so well-insulated that they have to move slowly and often rest to avoid getting overheated.

Similarly, in rainforests, Red-eyed frogs have developed sticky pads on their feet to help them climb trees on which they live.

Question 9:

How do elephants living in the tropical rainforest adapt itself?

Answer:

Following are the adaptation of elephants in rainforests

  • It uses the trunk as nose to have strong sense of smell
  • The trunk is also used to pick food
  • It has modified teeth tear the bark of trees which are food for elephants
  • Large ears of the elephant help it to hear even very soft sounds.
  • Ears help the elephant to keep cool in the hot and humid climate of the rainforest.

Choose the correct option which answers the following question:

Question 10:

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

Question 11:

Which features adapt polar bears to live in 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.

Question 12:

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 .

Science: Class 7th: Chapter 6: Physical and Chemical Changes

Question 1:

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) Chemical change

b) Physical Change

c) Chemical change

d) Physical Change

e) Physical Change

f) Chemical change

Question 2:

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

b) False

c) True

d) False

e) True

Question 3:

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 lime water, it turns milky due to the formation of Calcium carbonate.

(b) The chemical name of baking soda is Sodium hydrogen carbonate.

(c) Two methods by which rusting of iron can be prevented are painting and galvanization.

(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.

Question 4:

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 is mixed with lemon juice, bubbles are formed with the evolution of a carbon dioxide gas. This is a chemical change.

Lemon juice + Baking soda → Carbon dioxide + other substances

Question 5:

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:

Candle Burning

Physical change is melting of wax:

The chemical change is the burning of gas with the evolution of CO2

Digestion of Food

Physical change is the breakdown of larger food molecules to simpler ones

The chemical change is the digestion of food by the action of HCl and enzymes.

Question 6:

How would you show that the setting of curd is a chemical change?

Answer:

The setting of curd is a chemical change because curd cannot be turned back to milk. The properties of milk and curd are different.

Question 7:

Explain why burning of wood and cutting it into small pieces are considered as two different types of changes.

Answer:

Cutting of wood is a physical change as it does not change the nature of the wood. On the other hand, burning of wood is a chemical change as wood is converted to charcoal with the liberation of CO2.

Question 8:

Describe how crystals of copper sulphate are prepared.

Answer:

Crystals of copper sulphate are prepared using the crystallization method, which is described as follows

  • Take a cupful of water in a beaker.
  • Add a few drops of dilute sulphuric acid to this. 
  • Heat the water, and when it starts boiling, add copper sulphate powder while still stirring. 
  • Add the copper sulphate powder till the solution becomes saturated. Filter into a china dish and allow it to cool.
  • The solution should be kept undisturbed. Slowly, the crystals of copper sulphate separate out.

Question 9:

Explain how painting of an iron gate prevents it from rusting

Answer:

Rusting of iron requires contact with water (moisture) and oxygen. By painting an iron gate, we prevent the contact between iron, Oxygen and water(Moisture), this helps in preventing rusting of iron.

Question 10:

Explain why rusting of iron objects is faster in coastal areas than in deserts.

Answer:

Rusting of iron requires contact with water(moisture) and oxygen. In coastal areas, humidity is more in comparison to that in deserts; hence, rusting of iron objects is faster in coastal areas than in deserts.

Question 11:

The gas we use in the kitchen is called liquified petroleum gas (LPG). In the cylinder it exists as a liquid. When it comes out from the cylinder it becomes a gas (Change – A) then it burns (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:

(ii) Process – B is a chemical change.

Question 12:

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) Both processes A and B are chemical changes.

Science: Class 7th: Chapter 5 Acids, Bases, and Salts

Question 1:

State differences between acids and bases.

Answer:

AcidsBases
Acids are sour in tasteBases are bitter in taste
Acids turn blue litmus paper into red colorThe base does not change the colour of blue litmus paper
Acids does not change the colour of the red litmusBases turn red litmus paper to blue color

Question 2:

Ammonia is found in many household products, such as window cleaners. It turns red litmus blue. What is its nature?

Answer:

Basic in nature.

Question 3:

Name the source from which litmus solution is obtained. What is the use of this Answer?

Answer:

Litmus solution is extracted from lichens. Litmus solution is used as an indicator to find the acidic and basic nature of a solution.

Question 4:

Is the distilled water acidic/basic/neutral? How would you verify it?

Answer:

Distilled water is neutral in nature, and this can be tested by using red and blue litmus paper. In either of the cases, colour remains unchanged.

Question 5:

Describe the process of neutralisation with the help of an example.

Answer:

Neutralisation is a reaction between an acid and a base. Here both acids and bases get neutralised. For example, when sodium hydroxide (NaOH) is added to hydrochloric acid (HCl), sodium chloride (NaCl) and water (H2O) are obtained.

 NaOH + HCl → NaCl + H2O + Heat

Question 6:

Mark ‘T’ if the statement is true and ‘F’ if it is false:

(i) Nitric acid turns red litmus blue. (T/F)

(ii) Sodium hydroxide turns blue litmus red. (T/F)

(iii) Sodium hydroxide and hydrochloric acid neutralise each other and form salt and water. (T/F)

(iv) Indicator is a substance which shows different colours in acidic and basic Answers. (T/F)

(v) Tooth decay is caused by the presence of a base. (T/F)

Answer:

i) False

ii) False

iii) True

iv) True

v) False

Question 7:

Dorji has a few bottles of soft drink in his restaurant. But, unfortunately, these are not labelled. He has to serve the drinks on the demand of customers. One customer wants acidic drink, another wants basic and third one wants neutral drink. How will Dorji decide which drink is to be served to whom?

Answer:

Dorji can taste a few drops out of soft drinks bottles, acidic solution is sour in taste, basic solution is bitter in taste, and the neutral solution has no taste. Along with tasting, Dorji can use litmus paper to test the nature of soft drink. He should use blue litmus paper to test the acidic solution. Dorji has to put a drop of solution on blue litmus. If it turns red then the solution will be acidic in nature.

Similarly, he can use red litmus paper to test the basic solution. He has to put a drop of solution on red litmus. If it turns blue then the solution will be basic in nature.

Question 8:

Explain why:

(a) An antacid tablet is taken when you suffer from acidity

(b) Calamine solution is applied on the skin when an ant bites.

(c) Factory waste is neutralised before disposing it into the water bodies.

Answer:

  1. The antacid tablet contains a base like milk of magnesia which neutralises the acid produced in the stomach. Hence, it is used while suffering from acidity.
  1. When an ant bites, it injects formic acid inside the skin. Calamine consists of Zinc carbonate which is basic in nature. Hence calamine neutralises the effect of formic acid to bring relief for the affected person.
  1. Factory wastes are acidic in nature which may cause harm to aquatic life. Hence, they are neutralised by using a base before disposing it into the water bodies.

Question 9:

Three liquids are given to you. One is hydrochloric acid, another is sodium hydroxide and third is a sugar Answer. How will you identify them? You have only a turmeric indicator.

Answer:

Add solution to container with turmeric indicator. If the solution is NaOH, it would turn the turmeric indicator to red. To the same container, add test solution number 2. If the added solution is sugar, the solution indicator remains red because the mixture of basic and neutral solution will remain basic in nature.

Similarly, add the test solution number 3 to another container with a turmeric indicator. If the indicator remains red then the solution will be hydrochloric acid.

Question 10:

Blue litmus paper is dipped in a solution. It remains blue. What is the nature of the solution? Explain.

Answer:

Above solution may be neutral or basic in nature as both of them will not change the colour of the blue litmus paper.

Question 11:

Consider the following statements:

(a) Both acids and bases change colour of all indicators.

(b) If an indicator gives a colour change with an acid, it does not give a change with a base.

(c) If an indicator changes colour with a base, it does not change colour with an acid.

(d) Change of colour in an acid and a base depends on the type of the indicator. 

Which of these statements are correct?

(i) All four

(ii) a and d

(iii) b, c and d

(iv) only d

Answer:

(iv) only d

Science: Class 7th: Chapter 4 Heat

Question 1:

State similarities and differences between the laboratory thermometer and the clinical thermometer.

Answer:

Similarities

  • Both of them have a bulb at one end.
  • Bulbs of both the thermometers consist of mercury.
  • Celsius scale is present in both for measuring temperature.

Differences

Clinical ThermometerLaboratory thermometer
The temperature range is 35 – 42°CThe temperature range is  -10 -110°C
It is used to measure human body temperature.It is used to measure temperature in the laboratory.
It has kink which prevents immediate falling of temperature.It does not have a kink.

Question 2:

Give two examples each of conductors and insulators of heat.

Answer:

Conductors: 

Iron and Copper

Insulators: 

Plastic and wood

Question 3:

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. Heat is transferred to its other end by the process of ______________.

(f ) Clothes of ______________ colours absorb more 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 Celcius.

(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. Heat is transferred to its other end by the process of conduction.

(f ) Clothes of dark colours absorb more heat better than clothes of light colours.

Question 4:

Match the following:

Column-IColumn-II
(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(d) night

Answer:

Column-IColumn-II
(i) The land breeze blows during(d) night
(ii) The sea breeze blows during(c) day
(iii) Dark coloured clothes are preferred during(b) winter
(iv) Light coloured clothes are preferred during(a) summer

Question 5:

Discuss why wearing more layers of clothing during winter keeps us warmer than wearing just one thick piece of clothing.

Answer:

More layers of clothing during winter keeps us warmer than wearing just one thick piece of clothing because air would be trapped in-between layers. As air is a poor conductor of heat, it does not allow the escape of the heat from the body and thus we feel warm.

Question 6:

Look at Fig. 4.13. Mark where the heat is being transferred by conduction, by convection and by radiation.

conduction

Answer:

conduction radiation and convection

Question 7:

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 that the outer walls of houses be painted white because white colour reflects back most of the heat that is incident on it as white is a poor absorber of heat. So, less heat enters the house from outside.

Question 8:

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) between 30°C and 50°C

Question 9:

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) not flow from iron ball to water or from water to iron ball because both of them have the same temperature of 40°C.

Question 10:

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) does not become cold 

Question 11:

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 stainless steel.

(d) copper is easier to clean than the stainless steel

Answer:

(c) copper is a better conductor of heat than the stainless steel.

Science: Class 7th: Chapter 3 Fibre and Fabric

Question 1:

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 of the sheep. Mainly, the abdomen and back of the sheep have wool.

b)

White fleece of the lamb refers to the white colour of their fur which is used to make wool.

Question 2:

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

Question 3:

Which of the following does not yield wool?

(i) Yak (ii) Camel (iii) Goat (iv) Woolly dog

Answer:

(iv) Woolly dog

Question 4:

What is meant by the following terms? 

(i) Rearing 

(ii) Shearing 

(iii) Sericulture

Answer:

i) Raising of domestic animals like sheep, goat, yak, cow and buffaloes for commercial purposes such as for milk and fur is known as rearing.

ii) Shearing is a process of removal of animal hair by using machines.

ii) Rearing of silkworms for obtaining silk is known as Sericulture.

Question 5:

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, reeling, dying.

Question 6:

Make sketches of the two stages in the life history of the silk moth which are directly related to the production of silk.

Answer:

Question 7:

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

Question 8:

Match the words of Column I with those given in Column II:

Column-IColumn-II
1. Scouring(a) Yields silk fibres
2. Mulberry leaves(b) Wool yielding animal
3. Yak(c) Food of silkworm
4. Cocoon(d) Reeling
(e) Cleaning sheared skin

Answer:

Column-IColumn-II
1. Scouring(e) Cleaning sheared skin
2. Mulberry leaves(c) Food of silkworm
3. Yak(b) Wool yielding animal
4. Cocoon(a) Yields silk fibres
(d) Reeling

Question 9:

Given below is a crossword puzzle based on this lesson. Use hints to fill in the blank spaces with letters that complete the words.

Down

(D) 1 : Thorough washing

2 : Animal fibre

3 : Animal fibre

Across

(A) 1 : Keeps warm

2 : Its leaves are eaten by silkworms

3: Hatches from egg of moth

Puzzles of fibres and fabric

Answer:

Down:

1D. Scour

2D. Silk

3D. Fibre

Across:

1A. Wool

2A. Mulberry

3A. Caterpillar

Science:Class 7th:Chapter 2 Nutrition in Animals

Question 1:

Fill in the blanks:

(a) The main steps of nutrition in humans are _________, __________, __________, _________ and __________.

(b) The largest gland in the human body is __________.

(c) The stomach releases hydrochloric acid and ___________ juices which act on food.

(d) The inner wall of the small intestine has many finger-like outgrowths called _________.

(e) Amoeba digests its food in the ____________ .

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.

Question 2:

Mark ‘T’ if the statement is true and ‘F’ if it is false:

(a) Digestion of starch starts in the stomach. (T/F)

(b) The tongue helps in mixing food with saliva. (T/F)

(c) The gall bladder temporarily stores bile. (T/F)

(d) The ruminants bring back swallowed grass into their mouth and chew it for some time. (T/F)

Answer:

a) F

b) T

c) T

d) T

Question 3:

Tick mark the correct answer in each of the following:

(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

Answer:

a) (iii) small intestine

b) (iv) large intestine

Question 4:

Match the items of Column I with those given in Column II:

Column- IColumn- II
Food componentsProduct(s) of digestion
CarbohydratesFatty acids and glycerol
ProteinsSugar
FatsAmino acids

Answer:

Column- IColumn- II
Food componentsProduct(s) of digestion
CarbohydratesSugar
ProteinsAmino acids
FatsFatty acids and glycerol

Question 5:

What are villi? What is their location and function?

Answer:

Villi are the finger-like projections present on the inner walls of the small intestine.Their main function is to increase the surface area for the absorption of digested food.

Question 6:

Where is the bile produced? Which component of the food does it help to digest?

Answer:

Bile juice is produced in the liver. It helps in the digestion of fats by breaking large fat globules into smaller ones.

Question 7:

Name the type of carbohydrate that can be digested by ruminants but not by humans. Give the reason also.

Answer:

Cellulose is the carbohydrate that can be digested by ruminants but not by humans. Human beings lack the cellulose digesting enzyme. 

Question 8:

Why do we get instant energy from glucose?

Answer:

Glucose is a simple sugar and is easily absorbed by blood but other carbohydrates are first broken down into glucose and then absorbed, so glucose gives instant energy.

Question 9:

Which part of the digestive canal is involved in:

(i) absorption of food ________________.

(ii) chewing of food ________________.

(iii) killing of bacteria ________________.

(iv) complete digestion of food ________________.

(v) formation of faeces ________________.

Answer:

i) Small intestine

ii) Buccal cavity

iii)Stomach

iv) Small intestine

v) Large Intestine

Question 10:

Write one similarity and one difference between nutrition in amoeba and human beings.

Answer:

Similarity: Both amoeba and human beings require food for cellular processes.

Difference: Humans intake food through the buccal cavity. In amoeba food is ingested through pseudopodia.

Question 11:

Match the items of Column I with suitable items in Column II

Column-IColumn-II
a) Salivary gland(i) Bile juice secretion
b) Stomach(ii) Storage of undigested food
c) Liver(iii) Saliva secretion
d) Rectum(iv) Acid release
e) Small intestine(v) Digestion is completed
f) Large intestine(vi) Absorption of water
(vii) Release of faeces

Answer:

Column-IColumn-II
a) Salivary gland(iii) Saliva secretion
b) Stomach(iv) Acid release
c) Liver(i) Bile juice secretion
d) Rectum(ii) Storage of undigested food
e) Small intestine(v) Digestion is completed
f) Large intestine(vi) Absorption of water
(vii) Release of faeces

Question 12:

Label Fig. 2.11 of the digestive system.

Human digestive system

Answer:

Question 13:

Can we survive only on raw, leafy vegetables/grass? Discuss.

Answer:

No, we cannot survive only on raw, leafy vegetables because to have a healthy life, we should follow a balanced diet with all the nutrients. They mainly consist of cellulose and fibers which is not enough for the body. 

Science:Class 7th:Chapter 1 Nutrition in Plants

QUESTION 1:

Why do organisms need to take food?

Answer:

Every single living being requires energy for their life processes. Plants set up their food and procure supplements from abiotic segments like soil, air, water, and daylight. Then again, animals need to get food from either plants or different creatures to get supplements; henceforth creatures need to take food to get supplements and vitality.

QUESTION 2:

Distinguish between a parasite and saprophyte.

Answer:

PARASITESAPROPHYTE
Parasites derive supplements from  living organisms.They derive nutrients from dead and decaying stuff.
Parasites live in or on the host.They live on dead and decaying stuff.
Example:FungiExample:Roundworm

QUESTION 3:

How would you test the presence of starch in leaves?

Answer:

When starch interacts with iodine arrangement, it gives you a dark blue colour. So, when we add a couple of drops of iodine arrangement on the leaf and if the dark blue colour shows up, that will affirm the presence of starch in the leaves.

QUESTION 4:

Give the brief description of the process of synthesis of food in green plants.

Answer:

In green plants, the synthesis of food occurs by a process called photosynthesis. During this process, chlorophyll in the cells of the leaves utilises carbon dioxide and water to synthesize carbohydrates in the presence of sunlight. During this process oxygen is liberated and the formed carbohydrates is stored in the form of starch.  The process can be represented by an equation:

QUESTION 5:

Show with the help of a sketch that the plants are the ultimate source of food.

Answer:

QUESTION 6:

Fill in the blanks:

(a) Green plants are called ———– since they synthesize their own food. 

(b) The food synthesized by the plants is stored as —————. 

(c) In photosynthesis solar energy is captured by the pigment called ————. 

(d) During photosynthesis plants take in ————- and release ————–. 

Answer:

a. Green plants are called autotrophs since they synthesize their own food. 

b. The food synthesized 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. 

QUESTION 7:

Name the following: 

(a) A parasitic plant with yellow, slender and tubular stem. 

(b) A plant that has both autotrophic and heterotrophic mode of nutrition. 

(c) The pores through which leaves exchange gases. 

Answer:

(a) Cuscuta 

(b) Pitcher plant 

(c) Stomata

QUESTION 8:

Tick the correct answer: 

(a) Amarbel is an example of : 

(i) Autotroph 

(ii) Parasite 

(iii) Saprophyte 

(iv) Host 

(b) The plant which traps and feeds on insects is: 

(i) Cuscuta 

(ii) China rose 

(iii) Pitcher plant 

(iv) Rose 

Answer:

(a) (ii) Parasite 

(b) (iii) Pitcher plant

QUESTION 9:

Match the item in given column I with those in column II.

Column I Column II
Chlorophyll Bacteria 
Nitrogen Heterotrophs 
Amarbel Pitcher plant 
Animals Leaf 
Insects Parasite 

Answer:

Column IColumn II
Chlorophyll Leaf 
Nitrogen Bacteria 
Amarbel Parasite 
Animals Heterotrophs 
Insects Pitcher plant 

QUESTION 10:

Mark “T” if the statement is true and “F” if it is false: 

(i) Carbon dioxide is released during photosynthesis. (T/F) 

(ii) Plant which synthesis their food themselves are called saprotrophs. (T/F) 

(iii) The product of photosynthesis is not a protein. (T/F) 

(iv) Solar energy is converted into chemical energy during photosynthesis. (T/F) 

Answer:

(i) F

(ii)F

(iii)T

(iv)T

QUESTION 11:

Choose the correct option from the following: 

Which part of the plant gets carbon dioxide from the air for photosynthesis? 

(a) Root hair 

(b) Stomata 

(c) Leaf veins 

(d) Sepals 

Answer:

(b)Stomata

QUESTION 12:

Choose the correct option from the following: 

Plants take carbon dioxide from the atmosphere mainly through their: 

(a) Roots 

(b) Stem 

(c) Flowers 

(d) Leaves

Answer:

(d)Leaves