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NCERT Solutions for Class 12 Biology Chapter 14
Ecosystem Class 12
Chapter 14 Ecosystem Exercise Solutions
Exercise : Solutions of Questions on Page Number : 256
Q1 :
Fill in the blanks.
(a) Plants are called as_________ because they fix carbon dioxide.
(b) In an ecosystem dominated by trees, the pyramid (of numbers) is _________ type.
(c) In aquatic ecosystems, the limiting factor for the productivity is _________.
(d) Common detritivores in our ecosystem are_________.
(e) The major reservoir of carbon on earth is_________.
Answer :
(a) Plants are called as because they fix carbon dioxide.
(b) In an ecosystem dominated by trees, the pyramid (of numbers) is of type.
(c) In aquatic ecosystems, the limiting factor for productivity is .
(d) Common detritivores in our ecosystem are .
(e) A major reservoir of carbon on Earth is .
Q2 :
Which one of the following has the largest population in a food chain?
(a) Producers
(b) Primary consumers
(c) Secondary consumers
(d) Decomposers
Answer :
(d) Decomposers
Decomposers include micro-organisms such as bacteria and fungi. They form the largest population in a food chain
and obtain nutrients by breaking down the remains of dead plants and animals.
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Q3 :
The second trophic level in a lake is-
(a) Phytoplankton
(b) Zooplankton
(c) Benthos
(d) Fishes
Answer :
(b) Zooplankton
Zooplankton are primary consumers in aquatic food chains that feed upon phytoplankton. Therefore, they are present
at the second trophic level in a lake.
Q4 :
Secondary producers are
(a) Herbivores
(b) Producers
(c) Carnivores
(d) None of the above
Answer :
(d) None of the above
Plants are the only producers. Thus, they are called primary producers. There are no other producers in a food chain.
Q5 :
What is the percentage of photosynthetically active radiation (PAR), in the incident solar radiation.
(a) 100%
(b) 50 %
(c) 1-5%
(d) 2-10%
Answer :
(b) 50%
www.ncrtsolutions.in
NCERT Solutions for Class 12 Biology Chapter 14
Ecosystem Class 12
Chapter 14 Ecosystem Exercise Solutions
Exercise : Solutions of Questions on Page Number : 256
Q1 :
Fill in the blanks.
(a) Plants are called as_________ because they fix carbon dioxide.
(b) In an ecosystem dominated by trees, the pyramid (of numbers) is _________ type.
(c) In aquatic ecosystems, the limiting factor for the productivity is _________.
(d) Common detritivores in our ecosystem are_________.
(e) The major reservoir of carbon on earth is_________.
Answer :
(a) Plants are called as because they fix carbon dioxide.
(b) In an ecosystem dominated by trees, the pyramid (of numbers) is of type.
(c) In aquatic ecosystems, the limiting factor for productivity is .
(d) Common detritivores in our ecosystem are .
(e) A major reservoir of carbon on Earth is .
Q2 :
Which one of the following has the largest population in a food chain?
(a) Producers
(b) Primary consumers
(c) Secondary consumers
(d) Decomposers
Answer :
(d) Decomposers
Decomposers include micro-organisms such as bacteria and fungi. They form the largest population in a food chain
and obtain nutrients by breaking down the remains of dead plants and animals.
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, www.ncrtsolutions.in
Q3 :
The second trophic level in a lake is-
(a) Phytoplankton
(b) Zooplankton
(c) Benthos
(d) Fishes
Answer :
(b) Zooplankton
Zooplankton are primary consumers in aquatic food chains that feed upon phytoplankton. Therefore, they are present
at the second trophic level in a lake.
Q4 :
Secondary producers are
(a) Herbivores
(b) Producers
(c) Carnivores
(d) None of the above
Answer :
(d) None of the above
Plants are the only producers. Thus, they are called primary producers. There are no other producers in a food chain.
Q5 :
What is the percentage of photosynthetically active radiation (PAR), in the incident solar radiation.
(a) 100%
(b) 50 %
(c) 1-5%
(d) 2-10%
Answer :
(b) 50%
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