Case Study Questions Science Class 10th

Chapter 15: Our Environment

Case Study Question 01

Read the following passage carefully and answer the following questions:

Grazing food chains are directly dependent upon solar radiations as the primary source of energy. Green plants (or producers) form the first trophic level of the food chain. They synthesise their food by the process of photosynthesis. Herbivores or primary consumers feed upon the producers and form the second trophic level. Herbivores are eaten by carnivores of different categories. These are longer food chains.
Given below are 5 grazing food chains operating in the nature.Case_environ_01
Question.1. Select the option that correctly identifies P, Q and R.
PQR
(a)FrogDeerAquatic insect
(b)FrogElephantPhytoplankton
(c)TadpoleDeerZooplankton
(d)DogElephantAlgae

Question.2.
According to the given food chains which of the following animals is both secondary and tertiary consumer?

(a) Rabbit
(b) Tiger
(c) Eagle
(d) Small fish

(b) : Tiger is a secondary consumer in food chain B and tertiary consumer in food chain D.

Question.3.
Top consumer in which of the following food chains will have the maximum energy?

(a) Food chain A
(b) Food chain B
(c) Food chain C
(d) Food chain D

(a) : Top consumer of food chain A will have maximum energy as it is the shortest food chain.

Question.4.
If energy present in producers of food chain D is 20,000 KJ. Then amount of energy present in its secondary consumer will be

(a) 2000 KJ
(b) 20 KJ
(c) 2 KJ
(d) 200 KJ.

(d) : In food chain D, wild cat is the secondary consumer. Therefore, according to 10% law, amount of energy present in secondary consumer will be 200 KJ.

Question.5.
What will be the shape of pyramid of biomass of food chain E?

(a)(b) (c) (d)

(b) : Food chain E belongs to aquatic ecosystem. Therefore, its pyramid of biomass will be inverted.

Chapter 15: Our Environment

Case Study Question 02

Read the following passage carefully and answer the following questions:

Various components of an ecosystem maintain a balance in nature. Disturbance in any component of the environment cause an imbalance. One of the main environmental problem caused by human activities is global warming. Global warming is a phenomenon caused by the increasing concentration of greenhouse gases in the atmosphere resulting due to enhanced greenhouse effect.

Question.1.
Refer to the given pie chart showing the contribution of different gases to global warming.Identify gases P, Q, R and S and select the incorrect statement regarding them.

(a) P could be a gas that increases in atmosphere due to excessive use of fossil fuel.
(b) Q could be a gas produced by complete combustion of biomass.
(c) R could be synthetic gaseous compounds used as refrigerants in air conditioners and refrigerators.
(d) S could be a gas produced by combustion of nitrogen rich fuel.

(b) : In the given pie chart, gases P, Q, R and S respectively are `CO_{2}`, `CH_{4}`, `CFCs` and `N_{2}O`. Methane is produced by incomplete combustion of biomass.

Question.2.
What could not be a source of gas Q given in the above pie chart?

(a) Flooded paddy field
(b) Cattle
(c) Jet fuel
(d) Marshes

(c) : Methane (gas Q) is produced by incomplete biomass combustion and incomplete decomposition mostly by anaerobic methanogens. Flooded paddy fields, marshes and cattles are the major source of this gas.

Question.3.
If there is no `CO_{2}` in the atmosphere, then what will be the most likely consequence of this on the temperature of earth?

(a) The temperature remain unchanged as it depends upon the oxygen content of the atmosphere.
(b) The temperature would increase as less greenhouse gases will be absorbed by `CO_{2}`.
(c) The temperature would decrease as `CO_{2}` is the principal greenhouse gas.
(d) None of these

(c) : `CO_{2}` is the principal greenhouse gas that helps to keep the earth warm.

Chapter 15: Our Environment

Case Study Question 03

Study carefully the following figure representing greenhouse effect and answer the following questions:Case_environ_03

Question.1.
Select the correct statement regarding this.

(a) Much of the long wavelength infrared radiations re-radiated by the earth’s surface are absorbed by the atmospheric greenhouse gases.
(b) `CO_{2}`, `CH_{4}`, `CFCs` and `N_{2}O` are the gases which are responsible for greenhouse effect.
(c) The atmosphere is transparent to the incoming short-wavelength radiations and is translucent to the long-wavelength infrared radiations.
(d) All of these

(d) All of these

Question.2.
Greenhouse effect is due to

(a) accumulation of `O_{3}` and depletion of `CO_{2}`
(b) accumulation of both `O_{3}` and `CO_{2}`
(c) accumulation of `CO_{2}` and depletion of `O_{3}`
(d) presence of green plants on the earth.

(c) accumulation of `CO_{2}` and depletion of `O_{3}`

Chapter 15: Our Environment

Case Study Question 04

Refer the figure below carefully and answer the following questions:Case_environ_04

Question.1.
How are the organisms on Block 1 level best described as:

(a) primary consumers
(b) secondary consumers
(c) tertiary consumers
(d) decomposers

(a) primary consumers

Question.2.
In the figure given above what would be the amount of energy available at block 1 and block 2 levels if energy at producer level is 10,000 kcal?

(a) 1000 kcal and 100 kcal
(b) 100 kcal and 1000 kcal
(c) 10,000 kcal and 100 kcal
(d) 100 kcal and 10 kcal

(a) 1000 kcal and 100 kcal

Question.3.
What is represented by eagle at black 3?

(a) decomposers
(b) secondary consumers
(c) tertiary consumers
(d) predator

(c) tertiary consumer

Question.4.
After solar energy enters our atmosphere, which statement does not hold good regarding subsequent the events?

(a) Most of the radiation is absorbed by the Earth’s surface and used to warm the surface.
(b) Some of the solar radiation is reflected by Earth and atmosphere.
(c) Some of the infra-red radiation is absorbed by the atmosphere and re-emitted in all directions by the green-house gases.
(d) No infra-red radiation is emitted by Earth.

(d) No infra-red radiation is emitted by Earth

Question.5.
Energy flow diagram definitely conveys all the points given below, except:

(a) the flow of energy is multi-directional.
(b) the energy captured by the autotrophs does not return to the solar input.
(c) the energy that passes to the herbivores does not come back to the autotrophs.
(d) the energy moves progressively through the various trophic levels and it is no longer available to the previous level.

(a) the flow of energy is multi-directional

Chapter 15: Our Environment

Case Study Question 05

Refer the figure below carefully and answer the following questions:Case_environ_05

Question.1.
What is the name of the interrelation shown in this figure?

(a) Food chain
(b) Food web
(c) Trophic level
(d) Energy conservation

(b) Food web

Question.2.
The series of branching lines shown in above figure appears in nature because:

(a) the length and complexity of food chains vary.
(b) each organism is generally eaten by two or more other kinds of organisms.
(c) straight line food chains are not practically possible.
(d) all of the above

(d) all of the above

Question.3.
Which one of the following is true for a food web?

(a) Food web does not help in stabilising the ecosystem.
(b) secondary consumers cannot feed on other species in the event of decrease in population of prey.
(c) A food web provides alternative pathways of food availability.
(d) Food webs are straight.

(c) A food web provides alternative pathways of food availability.

Question.4.
The main source of energy flowing in any food web is the:

(a) animals
(b) consumer
(c) primary producer
(d) sun

(d) sun

Question.5.
In the picture shown above concentration of a chemical absorbed from soil is likely to be highest in:

(a) wildflowers
(b) grass
(c) coyote
(d) rabbit

(c) coyote

Chapter 15: Our Environment

Case Study Question 06

Read the following and answer the following questions:

The energy flow in the ecosystem is one of the major factors that support the survival of such a great number of organisms. For almost all organisms on earth, the primary source of energy is solar energy. It is amusing to find that we receive less than 50 per cent of the sun’s effective radiation on earth. When we say effective radiation, we mean the radiation, which can be used by plants to carry out photosynthesis.Case_environ_06

Question.1.
Every food chain in the ecosystem begins with _________. Which are the original?

(a) saprophytes
(b) parasites
(c) producers
(d) none of these

(c) Producers

Question.2.
If 100 J energy is available at the producer level in a food chain then the energy available to the secondary consumer will be:

(a) 10 J
(b) 0.1 J
(c) 1 J
(d) 0.01 J

(c) 1 J

Question.3.
The constituents which do not form eco-system are:

(a) Biotic constituents
(b) Plastic bags
(c) Abiotic constituents
(d) All of the above

(b) Plastic bags

Question.4.
Which of the two sets belong to the same trophic level?

(a) Frog : Lizard
(b) Rabbit : Tiger
(c) Vulture : Crow
(d) Deer : Hawk

(a) frog : lizard

Question.5.
A food chain comprising birds, green plants, fish and man. The concentration of harmful chemical entering the food chain will be maximum in:

(a) plant
(b) man
(c) birds
(d) fish

(b) man

Chapter 15: Our Environment

Case Study Question 07

Read the following and answer the following questions:

Frothing in Yamuna: The primary reason behind the formation of the toxic foam is high phosphate content in the wastewater because of detergents used in dyeing industries, dhobi ghats and households. Yamuna’s pollution level is so bad that parts of it have been labelled ‘dead’ as there is no oxygen in it for aquatic life to survive.Case_environ_07

Question.1.
Predict the pH value of the water of river Yamuna if the reason for froth is high content of detergents dissolved in it.

(a) 10-11
(b) 5-7
(c) 2-5
(d) 7

(a) 10-11

Question.2.
Which of the following statements is correct for the water with detergents dissolved in it?

(a) Low concentration of hydroxide ion (`OH^{-}`)and high concentration of hydronium ion (`H_{3}O^{+}`)
(b) High concentration of hydroxide ion (`OH^{-}`)and low concentration of hydronium ion (`H_{3}O^{+}`)
(c) High concentration of hydroxide ion (`OH^{-}`) as well as hydronium ion (`H_{3}O^{+}`)
(d) Equal concentration of both hydroxide ion (`OH^{-}`) and hydronium ion (`H_{3}O^{+}`).

(b) high concentration of hydroxide ion (`OH^{-}`)and low concentration of hydronium ion (`H_{3}O^{+}`)

Question.3.
The table provides the pH value of four solutions P, Q, R and S:

P2
Q9
R5
S11

Which of the following correctly represents the solutions in increasing order of their hydronium ion concentration?

(a) P > Q > R > S
(b) P > S > Q > R
(c) S < Q < R < P
(d) S < P < Q < R

(c) S < Q < R < P

Question.4.
High content of phosphate ion in river Yamuna may leads to:

(a) decreased level of dissolved oxygen and increased growth of algae.
(b) decreased level of dissolved oxygen and no effect of growth of algae.
(c) increased level of dissolved oxygen and increased growth of algae.
(d) decreased level of dissolved oxygen and decreased growth of algae.

(a) decreased level of dissolved oxygen and increased growth of algae.

Question.5.
If a sample of water containing detergents is provided to you, which of the following methods will you adopt to neutralise it?

(a) Treating the water with baking soda.
(b) Treating the water with vinegar.
(c) Treating the water with caustic soda.
(d) Treating the water with washing soda.

(b) Treating the water with vinegar.

Chapter 15: Our Environment

Case Study Question 08

Read the following and answer the following questions:

Biosphere is a global ecosystem composed of living organisms and abiotic factors from which they derive energy and nutrients. The ecosystem is defined as structural and functional unit of the biosphere comprising of living and non-living environment that interact by means of food chains and chemical cycles resulting in energy flow, biotic diversity and material cycling to form a stable, self-supporting system.Case_environ_08_1

Question.1.
Which trophic level is incorrectly defined?

(a) Carnivores–secondary or tertiary consumers.
(b) Decomposers–microbial heterotrophs
(c) Herbivores–primary consumers
(d) Omnivores–molds, yeast and mushrooms

(d) Omnivores–molds, yeast and mushrooms

Question.2.
The diagram below shows a food web from the sea shore. The mussel can be described as:Case_environ_08_02

(a) Producer
(b) Primary consumers
(c) Secondary consumer
(d) Decomposer

(c) Secondary consumers

Question.3.
The given figure best represents:Case_environ_08_03

(a) Grassland food chain
(b) Parasitic food chain
(c) Forest food chain
(d) Aquatic food chain

(a) Grassland food chain

Question.4.
Consider the following statements concerning food chains:

(i) Removal of 80% tigers from an area resulted in greatly increased growth of vegetation
(ii) Removal of most of the carnivores resulted in an increased population of herbivores.
(iii) The length of the food chains is generally limited to 3 – 4 trophic levels due to energy loss.
(iv) The length of the food chains may vary from 2 to 8 trophic levels.

Which two of the above statements are correct?

(a) (i), (iv)
(b) (i), (ii)
(c) (ii), (iii)
(d) (iii), (iv)

(c) (ii), (iii)

Question.5.
Which of the following groups of organisms are not included in ecological food chain?

(a) Carnivores
(b) Saprophytes
(c) Herbivores
(d) Predators

(b) Saprophytes

Chapter 15: Our Environment

Case Study Question 09

Take a look at the picture carefully and answer the following questions.:Case_environ_09

Question.1.
While designing an aquarium what are the things you would like to include to make it a complete ecosystem?

(a) Fishes, aquatic plants, pleco fish (algae eating fish), aerator, pebbles, fish food.
(b) Fishes, grass, plants, pleco fish (algae eating fish), fish food.
(c) Fishes, plants, oxygen pump, food, stones.
(d) Animals, fishes, plants, oxygen pump, food.

(a) Fishes, aquatic plants, pleco fish (algae eating fish), aerator, pebbles, fish food

Question.2.
Which one of the following is not a producer?

(a) Blue green algae
(b) Cactus
(c) Fungi
(d) Spinach

(c) Fungi

Question.3.
Herbivores, carnivores, omnivores, and parasites all come under:

(a) producers
(b) consumers
(c) ecosystem
(d) food web

(b) consumers

Question.4.
Which one is not true about an ecosystem?

(a) Ecosystem consists of living and non-living things both.
(b) Living organisms interact with each other.
(c) Growth, reproduction, and other activities of living organisms are not affected by the abiotic components of ecosystem.
(d) A garden is considered an ecosystem.

(c) Growth, reproduction, and other activities of living organisms are not affected by the abiotic components of ecosystem

Question.5.
Ecosystems can be of how many types?

(a) Two types – man-made and natural
(b) Two types – terrestrial and aquatic
(c) Four types – forests, ponds, lakes, and garden
(d) All of the above imply as correct answer.

(d) All of the above imply as correct answer.

Chapter 15: Our Environment

Case Study Question 10

Read the passage and answer the following questions:

Humans modify the environment around them through agriculture and urbanisation as the major activities. Human impact on the environment is so substantial that there is nothing left called pristine nature or ecosystems untouched by human intervention. The major impact of these interventions is ever increasing levels of all forms of pollution on our Earth. Waste disposal and depletion of ozone layer are two major concerns in this world.

Question.1.
Which one of the following sentences is not true about ozone?

(a) Ozone is a deadly poison.
(b) Ozone protects us from harmful UV rays emitted by the sun.
(c) Ozone is formed from oxygen in presence of UV rays.
(d) Ozone causes skin cancer in humans.

(d) Ozone causes skin cancer in humans.

Question.2.
Which one of the below given reason holds good for increase in the amount of waste generated by humans?

(a) Religious practices
(b) Change in packaging style and products
(c) Home cooking
(d) Use of plant-based products

(b) Change in packaging style and products

Question.3.
An environment enthusiast would certainly not choose one of these for a tea party at her home.

(a) Paper cups
(b) Thermocol cup
(c) Steel cup
(d) Earthen cups

(b) Thermocol cup

Question.4.
Which of the following groups contains a non-biodegradable item?

(a) Grass, flowers, lime-juice, and leather.
(b) Grass, wood, leather, and plastic.
(c) Cake, wood, flowers, and grass.
(d) Fruit-peels, cake, leather, and lime-juice.

(b) Grass, wood, leather, and plastic

Question.5.
Which of the following waste management plan is likely to work the best?

(a) Integrated waste management plan
(b) Recycling waste management plan
(c) Reducing waste management plan
(d) Reusing waste management plan

(a) Integrated waste management plan

Chapter 15: Our Environment

Case Study Question 11

Read the passage carefully and answer the following questions:

The waste generated by humans has been detrimental to our environment and is causing threat to our ecosystem. We are generating too much trash and failing to deal with it in a sustainable way. Every day we are disposing tons and tons of nonbiodegradable and unrecyclable waste into our oceans and landfills. Plastic waste is an example. In 2017 the Environmental Protection Agency in the US calculated that the total generation of municipal solid waste in the United States in 2017 was 267.8 million tons; compared with 2015 levels, it was a 5.7 million increase.

Question.1.
Non-biodegradable substances are:

(a) broken down by biological processes.
(b) not broken down by biological processes.
(c) prepared by biological processes.
(d) cannot be broken down by physical processes.

(b) not broken down by biological processes.

Question.2.
Which one of the following is not likely to happen in the case of solid waste disposal in landfills?

(a) Unpleasant odours
(b) Ground water pollution
(c) Fires and explosions
(d) Infrared radiation

(d) Infrared radiation.

Question.3.
Humans are not supposed to get any energy by eating coal, because:

(a) coal is harmful.
(b) coal is burnt.
(c) humans do not have enzymes to digest coal.
(d) coal is black.

(c) humans do not have enzymes to digest coal.

Question.4.
Man-made plastics are not bio-degradable because:

(a) they are hard.
(b) bacteria and saprophytes do not contain enzymes to decompose plastics.
(c) plastics are made in industries.
(d) plastics do not absorb water.

(b) bacteria and saprophytes do not contain enzymes to decompose plastics.

Question.5.
The depletion in the Ozone layer is caused by _________ .

(a) nitrous oxide
(b) carbon dioxide
(c) chlorofluorocarbons
(d) methane

(c) chlorofluorocarbons.

Chapter 15: Our Environment

Case Study Question 12

Read the following and answer the following questions:

The amount of ozone in the atmosphere has begun to drop sharply from 1980s. This decrease has been linked to synthetic chemicals. In 1987, the United Nations Environment Programme (UNEP) succeeded in forging an agreement to freeze harmful chemicals production at 1986 levels.Case_environ_12

Question.1.
At what level of atmosphere ozone layer is found?

(a) Troposphere
(b) Stratosphere
(c) Biosphere
(d) Ionosphere

(b) Stratosphere

Question.2.
At higher level of atmosphere radiations act upon oxygen molecule to form:

(a) oxygen
(b) ozone
(c) carbon monoxide
(d) all of the above

(b) Ozone

Question.3.
What is the major cause of ozone depletion?

(a) Chlorofluorocarbons
(b) Hydrochlorofluorocarbons
(c) Carbon tetrachloride and methyl chloroform
(d) All of the above

(d) All of the above

Question.4.
Which of the following sources is responsible for the depletion of ozone layer?

(a)a(b)b(c)c(d) All of the above

(d) All of the above

Question.5.
In which of the following countries Ozone hole has appeared?

(a) Africa
(b) North America
(c) Japan
(d) Antarctica

(d) Antarctica

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