CBSE Class 10 Biology Our Environment Worksheet Set B

Question. The percentage of solar radiation absorbed by all the green plants for the process of photosynthesis is about :
(a) 1%.
(b) 5%.
(c) 8%.
(d) 10%. 

Answer : A

Question. Which one of the following green house gases is a contributor due to incomplete combustion of coal and petroleum?
(a) Oxides of nitrogen
(b) Methane
(c) Carbon monoxide
(d) Carbon dioxide

Answer : C

Question. What happens to the earth's temperature due to the greenhouse effect?
(a) Increases
(b) Decreases
(c) Remains the same
(d) All of the above 

Answer : A

Question. Select the mismatched pair in the following and correct it.
(a) Bio-magnification — Accumulation of chemicals at the successive trophic levels of a food chain
(b) Ecosystem — Biotic components of environment
(c) Aquarium — A man-made ecosystem
(d) Parasites — Organisms which obtain food from other living organisms 

Answer : B

Question. In the given food chain, suppose the amount of energy at fourth trophic level is 5 kJ, what will be the energy available at the producer level? 
Grass → Grasshopper → Frog → Snake → Hawk
(a) 5 kJ
(b) 50 kJ
(c) 500 kJ
(d) 5,000 kJ 

Answer : D

Question. Organisms of a higher trophic level which feed on several types of organisms belonging to a lower trophic level constitute the ................... .
(a) Food web.
(b) Ecological pyramid.
(c) Ecosystem.
(d) Food chain. 

Answer : A

Question. Disposable plastic plates should not be used because
(a) They are made of materials with light weight.
(b) They are made of toxic materials.
(c) They are made of biodegradable materials.
(d) They are made of non-biodegradable materials.

Answer : D

Question. In a food chain, the third trophic level is always occupied by
(a) Carnivores.
(b) Herbivores.
(c) Decomposers.
(d) Producers. 

Answer : A

Question. Why is it difficult to degrade non-biodegradable wastes?
(a) Because non-biodegradable wastes cannot be recycled.
(b) Because microorganisms cannot decompose it.
(c) They can be made into organic wastes.
(d) All of the above 

Answer : B

Question. Excessive exposure of humans to UV-rays results in
(i) Damage to immune system.
(ii) Damage to lungs.
(iii) Skin cancer.
(iv) Peptic ulcers.
(a) (i) and (ii)
(b) (ii) and (iv)
(c) (i) and (iii)
(d) (iii) and (iv) 

Answer : C

Question. In an ecosystem, the 10% of energy available for transfer from one trophic level to the next is in the form of:
(a) Heat energy.
(b) Light energy.
(c) Chemical energy.
(d) Mechanical energy.

Answer : C

Question. Which one of the followings is an artificial ecosystem?
(a) Pond
(b) Crop field
(c) Lake
(d) Forest 

Answer : B

Question. Which of the followings are environment-friendly practices?
(a) Carrying cloth-bags to put purchases in while shopping.
(b) Switching off unnecessary lights and fans.
(c) Walking to school instead of getting your mother to drop you on her scooter.
(d) All of the above. 

Answer : D

Question. Which group of organisms are not constituents of a food chain?
(i) Grass, lion, rabbit, wolf
(ii) Plankton, man, fish, grasshopper
(iii) Wolf, grass, snake, tiger
(iv) Frog, snake, eagle, grass, grasshopper
(a) (i) and (iii)
(b) (iii) and (iv)
(c) (ii) and (iii)
(d) (i) and (iv) 

Answer : C

Question. Depletion of ozone is mainly due to _________.
(a) Chlorofluorocarbon compounds.
(b) Carbon monoxide.
(c) Methane.
(d) Pesticides. 

Answer : A

Question. Accumulation of non-biodegradable pesticides in the food chain in increasing amount at each higher trophic level is known as
(a) Eutrophication.
(b) Pollution.
(c) Biomagnification.
(d) Accumulation. 

Answer : C

Assertion and Reason Based MCQs :

Directions : In the following questions, A statement of Assertion (a) is followed by a statement of Reason (R). Mark the correct choice as.
(a) Both A and R are true and R is the correct explanation of A.
(b) Both A and R are true but R is NOT the correct explanation of A.
(c) A is true but R is false.
(d) A is false and R is true.

Question. Assertion (a): Herbivores are called first order consumers.
Reason (R): Tiger is a top carnivore. 

Answer : B

Question. Assertion (a): Decomposers keep the environment clean.
Reason (R): They recycle matter by breaking down the organic remains and waste products of plants and animals. 

Answer : A

Question. Assertion (a): Wastes such as plastics, paper, vegetable or fruit peels, which are generated in our house daily are biodegradable.
Reason (R): Biodegradable wastes can be broken down into simpler, harmless substance in nature in due course of time by the biological processes such as action of microorganisms. 

Answer : D

Question. Assertion (a): Polythene bags and plastic containers are non-biodegradable substances.
Reason (R): They can be broken down by microorganisms in natural simple harmless substances. 

Answer : C.

Question. Assertion (a): Flow of energy in a food chain is unidirectional.
Reason (R): Energy captured by autotrophs does not revert back to the solar input and it passes to the herbivores. 

Answer : A

Question. Assertion (a): The concentration of harmful chemicals is more in human beings.
Reason (R): Man is at the apex of the food chain. 

Answer : A

Question. Assertion (a): Greater number of individuals are present in lower trophic levels.
Reason (R): The flow of energy is unidirectional.

Answer : B

Question. Assertion (a): First trophic level in a food chain is always a green plant.
Reason (R): Green plants are called producers. 

Answer : A

Question. Assertion (a): Ozone is both beneficial and damaging.
Reason (R): Stop the release of chlorofluorocarbons to protect the ozone. 

Answer : B

Question. Assertion (a): Food chain is responsible for the entry of harmful chemicals in our bodies.
Reason (R): The length and complexity of food chains vary greatly. 

Answer : B

Question. Assertion (a): CFCs deplete the ozone layer.
Reason (R): CFCs are used as refrigerants and in fire extinguishers. 

Answer : A

Case-based MCQs :

Read the following and answer the four questions given below :

Food chains are very important for the survival of most species. When only one element is removed from the food chain it can result in extinction of a species in some cases. The foundation of the food chain consists of primary producers.
Primary producers, or autotrophs, can use either solar energy or chemical energy to create complex organic compounds, whereas species at higher trophic levels cannot and so must consume producers or other life that itself consumes producers. Because the sun's light is necessary for photosynthesis, most life could not exist if the sun disappeared. Even so, it has recently been discovered that there are some forms of life, chemotrophs, that appear to gain all their metabolic energy from chemosynthesis driven by hydrothermal vents, thus showing that some life may not require solar energy to thrive.

Question. Mr. X is eating curd/yogurt. For this food intake in a food chain he should be considered as occupying:
(a) First trophic level
(b) Second trophic level
(c) Third trophic level
(d) Fourth trophic level

Answer : C

Question. The decomposers are not included in the food chain. The correct reason for the same is because decomposers:
(a) Act at every trophic level of the food chain
(b) Do not breakdown organic compounds
(c) Convert organic material to inorganic forms
(d) Release enzymes outside their body to convert organic material to inorganic forms

Answer : A

Question. If 10,000 J solar energy falls on green plants in a terrestrial ecosystem, what percentage of solar energy will be converted into food energy? 
(a) 10,000 J
(b) 100 J
(c) 1000 J
(d) It will depend on the type of the terrestrial plant.

Answer : B

Question. Matter and energy are two fundamental inputs of an ecosystem. Movement of
(a) Energy is bidirectional and matter is repeatedly circulating.
(b) Energy is repeatedly circulation and matter is unidirectional.
(c) Energy is unidirectional and matter is repeatedly circulating.
(d) Energy is multidirectional and matter is bidirectional.

Answer : C

Carefully study the given food web and answer the four questions given below :

Question. Why do all food chains start with plants?
(a) Because plants are easily grown.
(b) Because plants are nutritious.
(c) Because plants can produce its own energy.
(d) Because plants do not require energy.

Answer : C

Question. 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

Answer : D

Question. The given figure best represents:

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

Answer : A

Question. In the food web, what two organism are competing for food?

(a) A and B
(b) A and C
(c) D and F
(d) B and D

Answer : D

Question. The mussel can be described as
(a) Producer
(b) Primary consumer
(c) Secondary consumer
(d) decomposer

Answer : C

Read the given passage and answer the questions given below :

Waste management is essential in today’s society. Due to an increase in population, the generation of waste is getting doubled day by day. Moreover, the increase in waste is affecting the lives of many people. 
Observe the following diagram and answer the questions any four from (i) to (v)

Waste management is the managing of waste by disposal and recycling of it. Moreover, waste management needs proper techniques keeping in mind the environmental situations. For instance, there are various methods and techniques by which the waste is disposed off. You must have come across 5 R’s to save the environment: refuse, reduce, reuse, repurpose and recycle.

Question. The given graph shows the amount of waste generated, dumped and treated in percentage.
Identify the reason of low success rate of waste management process.

(a) Only 15% of urban India’s waste is processed
(b) Less than 60% of waste is collected from households
(c) More than 60% of waste is collected from households
(d) Both (a) and (b)

Answer : D

Question. Recycling of paper is a good practice but recycled paper should not be used as food packaging because
(a) Recycled papers take lots of space.
(b) Recycled papers can’t cover food properly.
(c) Recycled papers can cause infection.
(d) Recycled papers are costly.

Answer : C

Question. Effective segregation of wastes at the point of generation is very important. Select the appropriate statements giving the importance of waste segregation.
(i) Less waste goes to the landfills
(ii) Better for public health and the environment
(iii) Help in reducing the waste
(iv) Resulting in deterioration of a waste picker’s health
(a) Both (i) and (ii)
(b) Both (i) and (iii)
(c) Both (ii) and (iii)
(d) Both (i) and (iv)

Answer : A

Question. Choose the waste management strategy that is matched with correct example.
(a) Refuse Choose products that use less packaging.
(b) Reduce Give unwanted toys and books to hospitals or schools.
(c) Reuse Not using single use plastic.
(d) Repurpose Making flower pot from used plastic bottle.

Answer : D

Question. According to the ‘Solid Waste Management Rule 2016’, the waste should be segregated into three categories.
Observe the table below and select the row that has correct information.

Answer : B

Read the following passage and answer the questions given below :

Human body is made up of five important components, of which water is the main component.
Food as well as potable water is essential for every human being. The food is obtained from plants through agriculture; Pesticides are being used extensively for a high yield in the fields. These pesticides are absorbed by the plants from the soil along with water and minerals and from the water bodies these pesticides are taken up by the aquatic animals and plants. As these chemicals are not biodegradable, they get accumulated progressively at each trophic level. The maximum concentration of these chemicals gets accumulated in our bodies and greatly affects the health of our mind and body.

Question. The maximum concentration of pesticides are found in
(a) Man
(b) Plants
(c) Deer
(d) Tiger

Answer : A

Question. With regard to various food chains operating in an ecosystem, man is a:
(a) Consumer
(b) Producer
(c) Producer and consumer
(d) Producer and decomposer

Answer : A

Question. Which of these methods could be applied to reduce our intake of pesticides through food to some extent ?
(a) Organic farming
(b) Mixed cropping
(c) Single cell protein
(d) Biofortification

Answer : A

Question. Various steps in a food chain represent:
(a) Food web
(b) Trophic level
(c) Ecosystem
(d) Bio-magnification

Answer : B

Based on the given information and your knowledge, answer the questions given below :

Food chains and the energy flow within an ecosystem provide an important understanding of contingencies and mutual dependencies of organisms.
The given below flow chart depicts the energy flow within some members of a grassland ecosystem. The grass in the below ecosystem transduces 120,000 J of sunlight and fixes it into 12,000 J of energy. It is established that 90% of the energy of one trophic level is not passed to the next trophic level. Further assume that the energy transferred from one trophic level to the next is equally shared among the different organisms at that trophic level.

Question. In the food web depicted above, identify the most energy efficient link for tertiary consumer.
(a) Rabbit
(b) Rat
(c) Lizard
(d) Grasshopper

Answer : A

Question. How many food chains are present in the food web depicted above?
(a) 2
(b) 3
(c) 5
(d) 6

Answer : C

Question. Based on the above information, indicate the amount of energy that an organism C may have received from an organism from the previous trophic level.
(a) 1,20,000 J
(b) 12, 000 J
(c) 1200 J
(d) 120 J

Answer : C

Question. Which organism acts as both the secondary consumer and the tertiary consumer?
(a) Snake
(b) Eagle
(c) Chicken
(d) Rat

Answer : B

Read the given passage and answer the questions given below :

A farmer is growing a crop regularly in his field. He uses chemical fertilizers, pesticides, organic manure as well as bio-fertilizers. Very close to his field is a factory which emits smoke as a byproduct. There is also a huge lake in the nearby area.

Question. ___________ is the increase in the concentration of harmful chemical substances in the body of living organisms.
(a) Biological oxygen demand
(b) Biomagnification
(c) Biosynthesis
(d) Biogeochemical cycle

Answer : B

Question. An expert agriculturist suggests to the farmer to minimize the use of chemical fertilizers and instead use biofertilizers as they have many advantages over chemical fertilizers.
Which of the following is NOT true for biofertilizers?
(a) They are economical
(b) They help in reducing pollution in the lake
(c) They are renewable
(d) They require large set-up for their production.

Answer : D

Question. A considerable increase in plant life in the lake was noticed after the farming activity intensified.
The most likely reason for this could be:
(a) Chemical fertilizers leached into the lake from the field.
(b) Pesticides leached into the lake from the field.
(c) Organic manure leached into the lake from the field.
(d) Smoke particles from the industry got settled in moist surroundings of the lake.

Answer : A

Question. Consider the following food chain in the same lake.
Aquatic plant → Small fish → Big fish → Birds Which of the above organisms is likely to show minimum amount of pesticide concentration in them after considerable time?
(a) Aquatic plants.
(b) Small fish.
(c) Big fish.
(d) Birds.

Answer : A

Study the passage and answer the questions given below :

The activities of man had adverse effects on all forms of living organisms in the biosphere.
Unlimited exploitation of nature by man disturbed the delicate ecological balance between the living and non-living components of the biosphere. The unfavourable conditions created by man himself threatened the survival not only of him but also of the entire living organisms on the mother earth. One of your classmates is an active member of ‘Eco club’ of your school which is creating environmental awareness amongst the school students, spreading the same in the society and also working hard for preventing environmental degradation of the surroundings.

Question. Which of the following does NOT exist in a balanced ecosystem?
(a) Interconnected food chains.
(b) Interdependence among living organisms and the environment.
(c) Animals dependent on plants but plants are not dependent on animals.
(d) Communities made up of different populations of organisms.

Answer : C

Question. Degradation of non-biodegradable waste is difficult because :
(a) Non-biodegradable wastes cannot be recycled.
(b) Microorganisms cannot decompose it.
(c) They can be made into organic wastes.
(d) All of the above

Answer : B

Question. Which of these group(s) contains only nonbiodegradable items?
(i) Wood, paper, leather
(ii) Polythene, detergent, PVC
(iii) Plastic, detergent, grass
(iv) Plastic, bakelite, DDT
(a) (iii)
(b) (iv)
(c) (i) and (iii)
(d) (ii) and (iv)

Answer : D

Question. The green dustbin signifies:
(a) Non- biodegradable waste
(b) Biodegradable waste
(c) Plastic waste
(d) Garbage

Answer : B

Question : Match the following with the correct response: 

a) 1-B, 2-D, 3-A, 4-C

b) 1-C, 2-B, 3-D, 4-A

c) 1-D, 2-A, 3-C, 4-B

d) 1-A, 2-C, 3-B, 4-D

Answer :  B

Explanation: Organisms can be grouped as producers, consumers and decomposers according to the manner in which they obtain their sustenance from the environment. Producers or autotrophs prepare their own food. Consumers can be classed as herbivores, carnivores, omnivores and parasites. Herbivores obtain food directly from green plants. Parasites obtain food from a host.

Short-Answer Questions