Q1Multiple choice
Which one of the following is an artificial ecosystem?
- (a)Pond
- (b)Crop field
- (c)Lake
- (d)Forest
Show answer
(b) Crop field
Chapter 15 – Our Environment
Class 10 Science · 38 questions · 38 with answers
Questions
Q2Multiple choice
In a food chain, the third trophic level is always occupied by
- (a)carnivores
- (b)herbivores
- (c)decomposers
- (d)producers
Show answer
(a) carnivores
Q3Multiple choice
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
Show answer
(c) both living organisms and non-living objects
Q4Multiple choice
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
Show answer
(d) 5000 k J
Q5Multiple choice
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
Show answer
(c) biomagnification
Q6Multiple choice
Depletion of ozone is mainly due to
- (a)chlorofluorocarbon compounds
- (b)carbon monoxide
- (c)methane
- (d)pesticides
Show answer
(a) chlorofluorocarbon compounds
Q7Multiple choice
Organisms which synthesise carbohydrates from inorganic compounds using radiant energy are called
- (a)decomposers
- (b)producers
- (c)herbivores
- (d)carnivores
Show answer
(b) producers
Q8Multiple choice
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
Show answer
(c) chemical energy
Q9Multiple choice
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
Show answer
(a) food web
Q10Multiple choice
Flow of energy in an ecosystem is always
- (a)unidirectional
- (b)bidirectional
- (c)multi directional
- (d)no specific direction
Show answer
(a) unidirectional
Q11Multiple choice
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) OUR ENVIRONMENT 107
Show answer
(c) (i) and (iii)
Q12Multiple choice
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)
Show answer
(d) (ii) and (iv)
Q13Multiple choice
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
Show answer
(a) Decrease in energy at higher trophic levels
Q14Multiple choice
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
Show answer
(b) Green plants get their food from organic compounds
Q15Multiple choice
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)
Show answer
(c) (ii) and (iii)
Q16Multiple choice
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 %
Show answer
(a) 1 %
Q17Multiple choice
In the given Figure 15.1 the various trophic levels are shown in a pyramid. At which trophic level is maximum energy available?
This question refers to a figure in the original PDF.
- (a)T4
- (b)T2
- (c)T1 Fig. 15.1
- (d)T3 108 E XEMPLAR P ROBLEMS – SCIENCE
Show answer
(c) T1 Fig. 15.1
Q18Multiple choice
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
Show answer
(d) The population of tiger decreases and the population of grass increases
Q19Multiple choice
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
Show answer
(b) convert organic material to inorganic forms
Q20Multiple choice
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
Show answer
(c) primary consumer to secondary consumer
Q21Multiple choice
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 5JQTV #PUYGT 3WGUVKQPU
Show answer
(d) they are made of non-biodegradable materials 5JQTV #PUYGT 3WGUVKQPU
Q22Short answer
Why is improper disposal of waste a curse to environment?
Show answer
Wastes pollute our environment, air, soil and water, and cause harmful effects on all living organisms.
Q23Short answer
Write the common food chain of a pond ecosystem.
Show answer
Phytoplanktons and aquatic plants → small aquatic animals larvae, insects etc) → fish → bird
Q24Short answer
What are the advantages of cloth bags over plastic bags during shopping?
Show answer
Cloth bags are (a) capable of carrying more things (b) made of biodegradable material (c) do not pollute our environment (d) can be reused
Q25Short answer
Why are crop fields known as artificial ecosystems?
Show answer
Crop fields are man made and some biotic and abiotic components are manipulated by humans
Q26Short answer
Differentiate between biodegradable and non-biodegradable substances. Cite examples. OUR ENVIRONMENT 109
Show answer
Substances that are broken down into simpler substances by biological processes are said to be biodegradable. Examples, wood, paper. Substances that cannot be broken down into simpler ones by biological processes are said to be non-biodegradable. Examples, plastic, DDT.
Q27Multiple choice
Suggest one word for each of the following statements/ definitions
- (a)The physical and biological world where we live in
- (b)Each level of food chain where transfer of energy takes place
- (c)The physical factors like temperature, rainfall, wind and soil of an ecosystem
- (d)Organisms which depend on the producers either directly or indirectly for food
Show answer
(a) The physical and biological world where we live in
(b) Each level of food chain where transfer of energy takes place
(c) The physical factors like temperature, rainfall, wind and soil of an ecosystem
(d) Organisms which depend on the producers either directly or indirectly for food
Q28Short answer
Explain the role of decomposers in the environment?
Show answer
Decomposers break down the dead and decaying organic matter and return the nutrients to the soil. Thus, they play a very important role in the nutrient re-cycling in the environment.
Q29Multiple choice
Select the mis-matched pair in the following and correct it.
- (a)Biomagnification — 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
Show answer
(b) Ecosystem — Biotic components of environment
(a) Biomagnification — Accumulation of chemicals at the successive trophic levels of a food chain
Q30Short answer
We do not clean ponds or lakes, but an aquarium needs to be cleaned. Why? .QPI #PUYGT 3WGUVKQPU
Show answer
An aquarium is an artificial and incomplete ecosystem in contrast to a pond/lake which are natural, self-sustaining and complete ecosystems. .QPI#PUYGT3WGUVKQPU
Q31Short answer
Indicate the flow of energy in an ecosystem. Why is it unidirectional? Justify.
Show answer
The flow of energy generally is Sun → producer → herbivore → carnivore. Since the flow is progressively from one trophic level to another and does not revert back, it is said to be undirectional. Further, the available energy decreases in the higher trophic levels making it impossible for energy to flow in the reverse direction.
Q32Short answer
What are decomposers? What will be the consequence of their absence in an ecosystem?
Show answer
Decomposers break down the complex organic substances of garbage, dead animals and plants into simpler inorganic substances that go into the soil and are used up again by the plants in the absence of decomposers recycling of material in the biosphere will not take place.
Q33Short answer
Suggest any four activities in daily life which are eco-friendly.
Show answer
Hints— (i) Separation of biodegradable and non-biodegradable substances. (ii) Gardening (iii) Use of gunny bags/paper bags in place of polythene/plastic bags (iv) Use of compost and vermicompost in place of fertilisers (v) Harvesting rain water
Q34Short answer
Give two differences between food chain and food web.
Show answer
Food chain Food Web (a) Food chain is a series of (a) Food web consists of a organisms feeding on number of interlinked one another food chains. (b) Members of higher (b) Members of higher trophic level feed upon trophic level can feed a single type of upon organisms of the organism of the lower lower trophic levels of trophic level other food chain. 174 E XEMPLAR P ROBLEMS – SCIENCE
Q35Short answer
Name the wastes which are generated in your house daily. What measures would you take for their disposal?
Show answer
Hints— (a) Kitchen wastes (b) Paper wastes like newspapers, bags, envelopes (c) Plastic bags (d) Vegetable/fruit peels/rind Measures for disposal (a) Segregation of biodegradable and non-biodegradable wastes. (b) Safe disposal of plastic bags. (c) Vegetable/fruit peels can be placed near trees/plants, which on decomposition will enrich the soil with nutrients. (d) Give paper wastes for recycling. (e) Prepare a compost pit for kitchen wastes.
Q36Short answer
Suggest suitable mechanism (s) for waste management in fertiliser industries.
Show answer
Hints— (a) Control air pollution (b) The effluent should be treated before discharge into surrounding environment.
Q37Short answer
What are the by-products of fertiliser industries? How do they affect the environment?
Show answer
The harmful by products are gases such as SO2 and NO. They cause extensive air pollution and are responsible for acid rain.
Q38Short answer
Explain some harmful effects of agricultural practices on the environment. 110 E XEMPLAR P ROBLEMS – SCIENCE
Show answer
Hints— (a) Excessive use of fertilisers changes the chemistry of soil and kills useful microbes. (b) Excessive use of non-biodegradable chemical pesticides leads to biological magnification. (c) Extensive cropping causes loss of soil fertility. (d) Excess use of ground water for agriculture lowers the water table. (e) Damage to natural ecosystem/habitat. ANSWERS 175 %*#26'4 ANSWERS /WNVKRNG%JQKEG3WGUVKQPU