Chapter 15. Our Environment

Class 10 Chapter 15 Our Environment Multiple Choice Questions and Answers :

Question :  Which of the following groups contain only biodegradable items?

(a) Grass, flowers and leather

(b) Grass, wood and plastic

(c) Fruit-peels, cake and lime-juice

(d) Cake, wood and grass

Answer :  (a) Grass, flowers and leather

(c) Fruit-peels, cake and lime-juice

(d) Cake, wood and grass

Question :  Which of the following constitute a food-chain?

(a) Grass, wheat and mango

(b) Grass, goat and human

(c) Goat, cow and elephant

(d) Grass, fish and goat

Answer :  (b) Grass, goat and human

Question :  Which of the following 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 :

Question : Which one of the following is a biodegradable waste ? [SEBA 2016]

(a) Polythene bag 

(b) Peeled skin of mango 

(c) Torn leather bag

(d) Plastic bottle

Answer :  (b) Peeled skin of mango

[ Biodegradable waste can be naturally broken down and decomposed by microorganisms, contributing to the recycling of nutrients in the environment.]

Question : Ozone, at the higher levels of atmosphere , prevents                . [SEBA 2017]

(a) infra-red radiations 

(b) Visible light

(c) UV radiations

(d) both (a) and (c)

Answer :  (c) UV radiations.

[ Ozone in the stratosphere absorbs and filters out a significant portion of the Sun's harmful ultraviolet (UV) radiation, particularly the most dangerous UV-B and UV-C rays. ]Top of Form

Question : Which of the following can depleted Ozone layer ? [SEBA 2023]

(a) Chloroflourocarbon 

(b) Nitrogen  

(c) Hydrogen  

(d) Oxygen   

Answer : (a) Chloroflourocarbon .

Question :  The 3rd trophic level of a food chain is  . [SEBA 2023]

Answer :   Secondary Consumers.

[ Third trophic level: Secondary Consumers, which are carnivores that eat the herbivores from the second trophic level .]

Question : Which one of the following is an artificial ecosystem?

(a) Pond

(b) Crop field

(c) Lake

(d) Forest

Answer : (b) Crop field 

[ A crop field is an example of an artificial ecosystem because it is created and maintained by human activities for the cultivation of crops, and it is not a naturally occurring ecosystem like a pond, lake, or forest.]

Question : In a food chain, the third trophic level is always occupied by

(a) carnivores

(b) herbivores

(c) decomposers

(d) producers

Answer : (a) carnivores:

[ The third trophic level in a food chain is typically occupied by carnivores, which are organisms that consume other animals.]

Question : An ecosystem includes

(a) all living organisms

(b) non-living objects

(c) both living organisms and non-living objects

(d) sometimes living organisms and sometimes non-living objects

Answer : (c) both living organisms and non-living objects

[ An ecosystem comprises both living organisms (biotic components) and non-living objects (abiotic components) in a specific area, interacting with each other and their environment.]

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 k J

(b) 50 k J

(c) 500 k J

(d) 5000 k J

Answer : (d) 5000 kJ.

[ Given that the energy at the fourth trophic level (hawk) is 5 kJ, we can work backward:

Energy at producer level = Energy at hawk level / .

Energy at producer level = 5 kJ / 0.001

Energy at producer level = 5000 kJ ]

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) biomagnification

[ The accumulation of non-biodegradable pesticides in increasing amounts at each higher trophic level in the food chain is known as biomagnification.]

Question : Depletion of ozone is mainly due to

(a) chlorofluorocarbon compounds

(b) carbon monoxide

(c) methane

(d) pesticides

Answer : (a) chlorofluorocarbon compounds

[ Depletion of ozone is mainly attributed to the release of chlorofluorocarbon (CFC) compounds into the atmosphere, which break down ozone molecules in the stratosphere. ]

Question : Organisms which synthesise carbohydrates from inorganic compounds using radiant energy are called

(a) decomposers

(b) producers

(c) herbivores

(d) carnivores

Answer : (b) producers

[ Organisms that synthesize carbohydrates from inorganic compounds using radiant energy (usually sunlight) through the process of photosynthesis are called producers.]

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) chemical energy

[ In an ecosystem, the 10% of energy available for transfer from one trophic level to the next is in the form of chemical energy stored in organic compounds, such as glucose, that make up the bodies of organisms.]

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) food web

[ Organisms of a higher trophic level that feed on several types of organisms belonging to a lower trophic level constitute a food web, which represents a complex network of interconnected food chains in an ecosystem. ]

Question : Flow of energy in an ecosystem is always

(a) unidirectional

(b) bidirectional

(c) multi directional

(d) no specific direction

Answer : (a) unidirectional

[ The flow of energy in an ecosystem is typically unidirectional, meaning it moves through the trophic levels from producers to consumers and decomposers in one direction.]

Question : Excessive exposure of humans to U V-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) (i) and (iii)

[ Excessive exposure to UV rays can result in damage to the immune system and an increased risk of skin cancer. ]

Question : In the following groups of materials, which group (s) contains only non-biodegradable 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) (ii) and (iv)

[ Polythene, detergent, PVC, plastic, bakelite, and DDT are all non-biodegradable materials, which do not easily break down in the environment.]

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

(a) Decrease in energy at higher trophic levels

(b) Dufficient food supply

(c) Polluted air

(d) Water

Answer : (a) Decrease in energy at higher trophic levels

[ The energy available to organisms decreases as it moves up the trophic levels in a food chain. This decrease in energy limits the number of trophic levels that can be supported in an ecosystem.]

Question : Which of the statement is incorrect?

(a) All green plants and blue green algae are producers

(b) Green plants get their food from organic compounds

(c) Producers prepare their own food from inorganic compounds

(d) Plants convert solar energy into chemical energy

Answer : (b) Green plants get their food from organic compounds

[ This statement is incorrect. Green plants are producers that use photosynthesis to convert inorganic compounds (such as carbon dioxide and water) into organic compounds (like glucose) using solar energy.]

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) (ii) and (iii)

[ In the given options, plankton, man, fish, and grasshopper belong to different trophic levels and do not form a direct linear sequence in a traditional food chain.]

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 : (b) 5%

[ Approximately 5% of solar radiation is absorbed by green plants for the process of photosynthesis.]

Question : In the given Figure 15.1 the various trophic levels are shown in a pyramid. At which trophic level is maximum energy available?

  

(a) T4

(b) T2

(c) T1

(d) T3

Answer : (c) T1

[ The trophic level at the base of the pyramid (T1) typically has the maximum energy available, as it represents the primary producers (plants) that capture energy from the sun.]

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

Grass → Deer → Tiger

(a) The population of tiger increases

(b) The population of grass decreases

(c) Tiger will start eating grass

(d) The population of tiger decreases and the population of grass increases

Answer : (d) The population of tiger decreases and the population of grass increases:

[ Without deer, the tiger's primary food source is missing, leading to a decrease in the tiger population and a potential increase in the grass population.]

Question : The decomposers in an ecosystem

(a) convert inorganic material, to simpler forms

(b) convert organic material to inorganic forms

(c) convert inorganic materials into organic compounds

(d) do not breakdown organic compounds

Answer : (b) convert organic material to inorganic forms

[ Decomposers break down organic material into simpler, inorganic compounds, facilitating the recycling of nutrients in an ecosystem by returning them to the soil.]

Question : If a grass hopper is eaten by a frog, then the energy transfer will be from

(a) producer to decomposer

(b) producer to primary consumer

(c) primary consumer to secondary consumer

(d) secondary consumer to primary consumer

Answer : (b) producer to primary consumer

[ The energy transfer occurs from the grasshopper (primary consumer) to the frog (secondary consumer), representing the flow of energy through different trophic levels in an ecosystem.]

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) they are made of non-biodegradable materials

[ Disposable plastic plates are often made from non-biodegradable materials, such as traditional petroleum-based plastics. These materials do not easily break down in the environment, leading to long-lasting pollution. This has negative impacts on ecosystems, wildlife, and human health. Choosing alternatives like biodegradable or reusable plates is generally considered more environmentally friendly.]