Class 10 Science Our Environment | NCERT Notes & Solutions

Q 1 :

The ________ is the functional unit of environment.

genus
class
ecosystem
biome

1

2

3

4

(2)

The ecosystem is the structural and functional unit of the environment through which various biotic and abiotic components interact with one another in relation to their surroundings.

Q 2 :

________ is not an abiotic factor.

Humidity
Temperature
Animals
Altitude

1

2

3

4

(2)

Both plants and animals are the biotic components of a habitat as they are the species that live there. The abiotic components of the ecosystem are non-living materials like rocks, soil, air, and water.

Q 3 :

________ are biotic factors.

Mountains
Grass
Rocks
All of these

1

2

3

4

(3)

Any living component that impacts another organism or shapes the environment is referred to as a biotic component, or biotic factor. Animals, plants, grass, fungus, bacteria, and protists are examples of biotic factors.

Q 4 :

A ________ is considered a terrestrial ecosystem.

ocean
pond
underground caves
forest

1

2

3

4

(4)

A terrestrial ecosystem is a land-based population of species that includes biotic and abiotic interactions in a specific area. Therefore a forest is considered a terrestrial ecosystem.

Q 5 :

Which of the following is an abiotic component of the ecosystem?

Lichens on a bare rock
Weathered rock
Planktons in a pond
Sea-weed

1

2

3

4

(2)

Weathered rock is an abiotic or non-living component of the ecosystem.

Q 6 :

Lakes and ponds do not require cleaning but an aquarium does because

an aquarium is an artificial and a complete ecosystem.
lakes and ponds are natural and complete ecosystems.
an aquarium possesses a pool of decomposers.
lakes do not possess any decomposers and thus BOD always remains low.

1

2

3

4

(2)

Lakes and ponds do not require cleaning but an aquarium does because an aquarium is an artificial ecosystem. It is complete and lacks natural decomposers.

Q 7 :

Four students gave 4 different statements about ecosystem. Who is incorrect?

Student A: “Energy can be recycled in an ecosystem.”
Student B: “Matter cannot be recycled in an ecosystem.”
Student C: “Energy cannot be recycled but matter can be recycled in an ecosystem.”
Student D: “Neither energy nor matter can be recycled in an ecosystem.”

Both students A and B
Students A, B and D
Student C
Students A and C

1

2

3

4

(2)

In an ecosystem, the sun is the only source of energy. The energy is not recycled, but the organic matter, which passes from one trophic level to the next, is recycled by the action of decomposers.

Q 8 :

Fishes living in a crop field with standing water are the part of a/an ________ ecosystem.

natural
indigenous
artificial
none of these

1

2

3

4

(2)

Crop fields are man-made ecosystems. If these have standing water as in the case of rice field, they can be used to culture fish. The fish in this water would be the part of an artificial ecosystem.

Q 9 :

Which of the following is NOT a type of natural ecosystem?

Sea
Crop field
Lakes and ponds
Estuaries

1

2

3

4

(2)

A crop field is made by humans. Hence, it is not a type of natural ecosystem.

Q 10 :

Which of the following statements is incorrect?

All green plants and blue green algae are producers.
Green plants get their food from organic compounds.
Producers prepare their own food from inorganic compounds.
Plants convert solar energy into chemical energy.

1

2

3

4

(2)

Green plants and algae are both producers which means that they can make their own food with the help of inorganic substances and sun energy, through the process of photosynthesis.

Q 11 :

________ are producers

Amoeba
Mushrooms
Sunlight
Green plants

1

2

3

4

(4)

Green plants are producers. They produce their own food, which provides them with the energy they require to grow, reproduce, and survive. They are the only living beings on earth capable of producing their own supply of food energy, which makes them unique.

Q 12 :

The % of solar radiation absorbed by all the green plants for the process of photosynthesis is about:

1%
5%
8%
10%

1

2

3

4

(1)

For the process of photosynthesis, green plants capture roughly 1% of the energy of sunlight that falls on their leaves. This energy is converted into chemical energy, which is then used to make food.

Q 13 :

All the organisms are not capable of utilising the sun’s energy directly for meeting their energy requirements. This gap is filled by:

(i) all green plants
(ii) some species of bacteria
(iii) algae
(iv) all bacterial species and plant species

(ii) and (iv)
(ii) and (iii)
(i), (ii) and (iii)
Only (i)

1

2

3

4

(3)

All green plants, some species of bacteria and green algae are capable of converting sunlight into a useful form by the process of photosynthesis.

Q 14 :

Which of the following would be affected by the decrease in the producer population?

All the organisms in the ecosystem.
The organisms in the next trophic level.
The organisms at the highest trophic level.
None of the organisms in the food chain will be affected.

1

2

3

4

(1)

A decrease in the population of producers would directly and indirectly affect all the organisms in that ecosystem.

Q 15 :

Which of the following statements is correct?

All plants and bacteria are producers.
All green plants and certain bacteria are producers.
Only some species of green plants and all bacteria are producers.
Only green plants are producers.

1

2

3

4

(2)

All green plants and certain bacteria are producers in an ecosystem.

Q 16 :

In presence of , along with sunlight is required to make organic compounds.

producers; chlorophyll
decomposers; chlorophyll
producers; carbon
consumers; carbon

1

2

3

4

(1)

In producers, the presence of chlorophyll, along with sunlight is required to produce glucose.

Q 17 :

The decomposers in an ecosystem:

convert inorganic material to simpler forms.
convert organic material to inorganic forms.
convert inorganic materials into organic compounds.
do not break down organic compounds.

1

2

3

4

(2)

Decomposers in an ecosystem transform organic material into inorganic forms, which are then reused by plants in the soil. Decomposers eat dead bodies, waste products, and organisms.

Q 18 :

What will happen if deer is missing in the food chain given below?

$G r a s s \to D e e r \to T i g e r$

The population of tiger increases.
Tiger will start eating grass.
The population of grass decreases.
The population of tiger decreases and the population of grass increases.

1

2

3

4

(4)

The tiger is a secondary consumer which eats deer. If the deer is missing, there will be no food for the tiger. So, if deers are missing, the population of grass will increase.

Q 19 :

Food chain does not comprise of which of the following groups of organisms?
(i) Grass, lion, rabbit, wolf
(ii) Plankton, man, fish, grasshopper
(iii) Wolf, grass, snake, tiger
(iv) Frog, snake, eagle, grass, grasshopper

(i), (iii)
(iii), (iv)
(ii), (iii)
(i), (iv)

1

2

3

4

(3)

The flow of energy from one organism to another taking part at various biotic levels forms a food chain. A food chain describes the feeding relationships between the organisms within that ecosystem. Food chain (ii) is an aquatic food chain so grasshopper cannot be a part of it. In food chain (iii), wolf, snake and tiger all are carnivores. There is no herbivore to eat grass or herbivore is missing from the chain.

Q 20 :

Why do all food chains start with plants?

Because plants are easily grown.
Because plants are nutritious.
Because plants can produce its own energy.
Because plants do not require energy.

1

2

3

4

(3)

A food chain starts with a plant. This is because every food chain needs the presence of organisms that can manufacture their own food. Green plants are called as producers as they can synthesise their own food in the presence of sunlight and therefore, most of the food chains start with plants.

Q 21 :

Which of the following limits the number of trophic levels in a food chain?

Decrease in energy at higher trophic levels
Deficient food supply
Polluted air
Water

1

2

3

4

(1)

A considerable amount of energy is used to keep organisms alive at each trophic level. As an organism progresses through the trophic levels, it receives less and less energy. The number of trophic levels is restricted to 3–4 since the energy available for the next level is insufficient to keep the organisms alive after that.

Q 22 :

Hydrogen is labelled ‘brown’ if the manufacturing process releases both carbon dioxide and carbon monoxide to the air.

In what way is the manufacturing process of brown hydrogen WORSE than that of grey hydrogen for the environment?

It releases into the atmosphere a gas that directly causes a greenhouse effect.
It releases into the atmosphere carbon which was stored for millions of years.
It releases into the atmosphere a gas that is toxic to human beings.
It releases into the atmosphere gases that cause acid rain.

1

2

3

4

(1)

Brown hydrogen is produced by gasification, where carbonous materials are heated into a gas. This extraction process involves turning coal into gas and produces large quantities of carbon emissions that are released into the atmosphere leading to the formation of greenhouse gases responsible for ozone depletion.

Q 23 :

If a grasshopper is eaten by a frog, then the energy transfer will be from:

producer to decomposer
producer to primary consumer
primary consumer to secondary consumer
secondary consumer to primary consumer

1

2

3

4

(3)

If a frog eats a grasshopper, energy is transferred from primary consumer to secondary consumer in a food chain. Grasshoppers eat producers, such as grass and plants. So, it is classified as a primary consumer. As a result, frogs, which eat grasshoppers, become the secondary consumer.

Q 24 :

Organisms of a higher trophic level which feed on several types of organisms belonging to a lower trophic level constitute the:

food web
ecological pyramid
ecosystem
food chain

1

2

3

4

(1)

A food web is a network of interrelated food chains. In a food chain, a creature can occupy more than one trophic level. It eats a variety of organisms of lower trophic level and may be devoured by organisms of higher trophic level.

Q 25 :

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?

$G r a s s \to G r a s s h o p p e r \to F r o g \to S n a k e \to H a w k$

5 kJ
50 kJ
500 kJ
5000 kJ

1

2

3

4

(4)

According to the 10 per cent law, only 10% of the energy available in a trophic level is passed on to the next trophic level. As a result, if the energy available at the fourth trophic level is 5 kJ, then the energy available at the producer level is 5000 kJ:
$5 \to 50 \to 500 \to 5000 .$

Q 26 :

At which trophic level is maximum energy available in the figure given below for the various trophic levels in a food chain?

$T ₄$
$T ₂$
$T ₁$
$T ₃$

1

2

3

4

(3)

All ecosystems are characterised by a unidirectional flow of energy. At each trophic level, most of the energy available is utilised for respiration and excretion and only ten percent of the available energy is passed on to the next level because only ten percent of the available energy can be passed on to the next trophic level. Higher trophic levels have substantially less energy content and the number of trophic levels in a food chain is limited. The lower the trophic level, the higher will be energy content. Hence, the greatest amount of energy is expected to be in trophic level $T ₁$ .

Q 27 :

In the food web, which two organisms are competing for food?

A and B
A and C
D and F
B and D

1

2

3

4

(4)

When members of various species compete for the same resource in an environment, competition develops. Here, B and D are competing for the same resources or food in this food web.

Q 28 :

In an area, the frog population decreased due to the spread of some diseases. Frogs are prey for snakes, but no major effect was seen in the population of snakes. Instead, there was a decline in the pesticide sale. What could be the possible reason?

Frogs stopped eating grains due to their infection.
There is no relation between the decrease in frog population and pesticide sales.
Both frog and snake migrated to some other area
Snakes now depended on other organisms that must be the pests for the crops grown.

1

2

3

4

(4)

Given scenario is an example of a food web. Infection in frogs could have possibly made snakes shift towards another prey such as rats. Rats destroy the stocked grains. When snakes started eating rats, the sale of pesticides against rats decreased.

Q 29 :

Supriya listed some important points for energy transfer in a food chain. She made an error. Point out that error.

(i) Primary consumers transfer 10% of energy to the next trophic level in the food chain.
(ii) The population at a lower trophic level is greater than the population at a higher trophic level.
(iii) Producers depend entirely on sunlight to make food.
(iv) Decomposers work at a double pace to convert complex molecules into simpler forms in case of an epidemic.

Only (ii)
Only (iv)
(i) and (iii)
All of these

1

2

3

4

(2)

The populations at a lower trophic are greater in number than the populations at higher trophic level to fulfil the energy demand of the latter. The population of decomposers might vary but not the pace.

Q 30 :

Which of the statements given below is correct?

Omnivores are in the middle of the food chain.
Omnivores are either in the middle or at the top of the food chain.
Omnivores are at the top of the food chain.
Omnivores are capable of modifying the natural food chain.

1

2

3

4

(2)

Omnivores can consume plants (producers) as well as animals (consumers). They can be at the middle just after plants or at the top of the food chain.

Topic Question Set

Q 1 :

The ________ is the functional unit of environment.

Q 2 :

________ is not an abiotic factor.

Q 3 :

________ are biotic factors.

Q 4 :

A ________ is considered a terrestrial ecosystem.

Q 5 :

Which of the following is an abiotic component of the ecosystem?

Q 6 :

Lakes and ponds do not require cleaning but an aquarium does because

Q 8 :

Fishes living in a crop field with standing water are the part of a/an ________ ecosystem.

Q 9 :

Which of the following is NOT a type of natural ecosystem?

Q 10 :

Which of the following statements is incorrect?

Q 11 :

________ are producers

Q 12 :

The % of solar radiation absorbed by all the green plants for the process of photosynthesis is about:

Q 13 :

All the organisms are not capable of utilising the sun’s energy directly for meeting their energy requirements. This gap is filled by:

(i) all green plants
(ii) some species of bacteria
(iii) algae
(iv) all bacterial species and plant species

Q 14 :

Which of the following would be affected by the decrease in the producer population?

Q 15 :

Which of the following statements is correct?

Q 16 :

In presence of , along with sunlight is required to make organic compounds.

Q 17 :

The decomposers in an ecosystem:

Q 18 :

What will happen if deer is missing in the food chain given below?

$G r a s s \to D e e r \to T i g e r$

Q 19 :

Food chain does not comprise of which of the following groups of organisms?
(i) Grass, lion, rabbit, wolf
(ii) Plankton, man, fish, grasshopper
(iii) Wolf, grass, snake, tiger
(iv) Frog, snake, eagle, grass, grasshopper

Q 20 :

Why do all food chains start with plants?

Q 21 :

Which of the following limits the number of trophic levels in a food chain?

Q 22 :

Hydrogen is labelled ‘brown’ if the manufacturing process releases both carbon dioxide and carbon monoxide to the air.

In what way is the manufacturing process of brown hydrogen WORSE than that of grey hydrogen for the environment?

Q 23 :

If a grasshopper is eaten by a frog, then the energy transfer will be from:

Q 24 :

Organisms of a higher trophic level which feed on several types of organisms belonging to a lower trophic level constitute the:

Q 25 :

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?

$G r a s s \to G r a s s h o p p e r \to F r o g \to S n a k e \to H a w k$

Q 26 :

At which trophic level is maximum energy available in the figure given below for the various trophic levels in a food chain?

Q 27 :

In the food web, which two organisms are competing for food?

Q 28 :

In an area, the frog population decreased due to the spread of some diseases. Frogs are prey for snakes, but no major effect was seen in the population of snakes. Instead, there was a decline in the pesticide sale. What could be the possible reason?

Q 30 :

Which of the statements given below is correct?

Want Us to Email you About Special Offers & Updates?

Topic Question Set

Q 1 : The ________ is the functional unit of environment.

Q 2 : ________ is not an abiotic factor.

Q 3 : ________ are biotic factors.

Q 4 : A ________ is considered a terrestrial ecosystem.

Q 5 : Which of the following is an abiotic component of the ecosystem?

Q 6 : Lakes and ponds do not require cleaning but an aquarium does because

Q 8 : Fishes living in a crop field with standing water are the part of a/an ________ ecosystem.

Q 9 : Which of the following is NOT a type of natural ecosystem?

Q 10 : Which of the following statements is incorrect?

Q 11 : ________ are producers

Q 12 : The % of solar radiation absorbed by all the green plants for the process of photosynthesis is about:

Q 13 : All the organisms are not capable of utilising the sun’s energy directly for meeting their energy requirements. This gap is filled by: (i) all green plants (ii) some species of bacteria (iii) algae (iv) all bacterial species and plant species

Q 14 : Which of the following would be affected by the decrease in the producer population?

Q 15 : Which of the following statements is correct?

Q 16 : In ________ presence of ________, along with sunlight is required to make organic compounds.

Q 17 : The decomposers in an ecosystem:

Q 18 : What will happen if deer is missing in the food chain given below? Grass → Deer → Tiger

Q 19 : Food chain does not comprise of which of the following groups of organisms? (i) Grass, lion, rabbit, wolf (ii) Plankton, man, fish, grasshopper (iii) Wolf, grass, snake, tiger (iv) Frog, snake, eagle, grass, grasshopper

Q 20 : Why do all food chains start with plants?

Q 21 : Which of the following limits the number of trophic levels in a food chain?

Q 22 : Hydrogen is labelled ‘brown’ if the manufacturing process releases both carbon dioxide and carbon monoxide to the air. In what way is the manufacturing process of brown hydrogen WORSE than that of grey hydrogen for the environment?

Q 23 : If a grasshopper is eaten by a frog, then the energy transfer will be from:

Q 24 : Organisms of a higher trophic level which feed on several types of organisms belonging to a lower trophic level constitute the:

Q 25 : 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

Q 26 : At which trophic level is maximum energy available in the figure given below for the various trophic levels in a food chain?

Q 27 : In the food web, which two organisms are competing for food?

Q 28 : In an area, the frog population decreased due to the spread of some diseases. Frogs are prey for snakes, but no major effect was seen in the population of snakes. Instead, there was a decline in the pesticide sale. What could be the possible reason?

Q 30 : Which of the statements given below is correct?

Want Us to Email you About Special Offers & Updates?

Q 1 :

The ________ is the functional unit of environment.

Q 2 :

________ is not an abiotic factor.

Q 3 :

________ are biotic factors.

Q 4 :

A ________ is considered a terrestrial ecosystem.

Q 5 :

Which of the following is an abiotic component of the ecosystem?

Q 6 :

Lakes and ponds do not require cleaning but an aquarium does because

Q 8 :

Fishes living in a crop field with standing water are the part of a/an ________ ecosystem.

Q 9 :

Which of the following is NOT a type of natural ecosystem?

Q 10 :

Which of the following statements is incorrect?

Q 11 :

________ are producers

Q 12 :

The % of solar radiation absorbed by all the green plants for the process of photosynthesis is about:

Q 13 :

All the organisms are not capable of utilising the sun’s energy directly for meeting their energy requirements. This gap is filled by:

(i) all green plants
(ii) some species of bacteria
(iii) algae
(iv) all bacterial species and plant species

Q 14 :

Which of the following would be affected by the decrease in the producer population?

Q 15 :

Which of the following statements is correct?

Q 16 :

In presence of , along with sunlight is required to make organic compounds.

Q 17 :

The decomposers in an ecosystem:

Q 18 :

What will happen if deer is missing in the food chain given below?

$G r a s s \to D e e r \to T i g e r$

Q 19 :

Food chain does not comprise of which of the following groups of organisms?
(i) Grass, lion, rabbit, wolf
(ii) Plankton, man, fish, grasshopper
(iii) Wolf, grass, snake, tiger
(iv) Frog, snake, eagle, grass, grasshopper

Q 20 :

Why do all food chains start with plants?

Q 21 :

Which of the following limits the number of trophic levels in a food chain?

Q 22 :

Hydrogen is labelled ‘brown’ if the manufacturing process releases both carbon dioxide and carbon monoxide to the air.

In what way is the manufacturing process of brown hydrogen WORSE than that of grey hydrogen for the environment?

Q 23 :

If a grasshopper is eaten by a frog, then the energy transfer will be from:

Q 24 :

Organisms of a higher trophic level which feed on several types of organisms belonging to a lower trophic level constitute the:

Q 25 :

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?

$G r a s s \to G r a s s h o p p e r \to F r o g \to S n a k e \to H a w k$

Q 26 :

At which trophic level is maximum energy available in the figure given below for the various trophic levels in a food chain?

Q 27 :

In the food web, which two organisms are competing for food?

Q 28 :

In an area, the frog population decreased due to the spread of some diseases. Frogs are prey for snakes, but no major effect was seen in the population of snakes. Instead, there was a decline in the pesticide sale. What could be the possible reason?

Q 30 :

Which of the statements given below is correct?