Topic: Ecosystem (Test 3)



Topic: Ecosystem
Q.1
Among desert plants, which of the following will become a limiting for primary production
A. light
B. water
C. chlorophyll
D. temperature
Answer : Option B
Explaination / Solution:

Primary productivity is of plants depends upon availability of water, sunlight, chlorophyll, carbon dioxide etc. but in desert plants water is the main limiting factor as very less amount of water is available to plants in deserts.

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Q.2
Which of the following may cause algal blooms in the aquatic system:
A. carbon
B. sulphur
C. phosphorus
D. Oxygen
Answer : Option C
Explaination / Solution:

Algal bloom is rapid increase in population of algae is a water system. This is caused due to excess of nutrients like phosphorus and nitrogen in the water bodies.

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Q.3
Sparrow is
A. only consumer
B. both 1consumer and 2consumer
C. only consumer
D.  consumer
Answer : Option B
Explaination / Solution:

Sparrow feeds on fruits as well insects. Herbivores or plant eaters are primary consumer and carnivores that feed on herbivores are secondary consumer. So, Sparrow occupy both primary and secondary trophic levels.

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Q.4
The first order consumers are called:
A. Chemotrophs
B. Herbivores
C. Autotrophs
D. Producers
Answer : Option B
Explaination / Solution:

Plants and algae make their own food and are called primary producers. Herbivores eat plants and are called primary consumers.

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Q.5
We can save those water reservoirs which are useful for irrigation, by
A. allowing silting
B. checking biotic succession
C. allowing eutrophication
D. providing conditions suitable for secondary succession
Answer : Option B
Explaination / Solution:

We can save water reservoirs which are useful for irrigation by checking biotic succession. Biotic succession leads to silt formation at bottom that reduce the capacity of water reservoirs.

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Q.6
In a rain shadow area biome is represented by
A. Desert
B. Tundra
C. Taiga
D. Evergreen forests
Answer : Option A
Explaination / Solution:

A rain shadow is a dry area on the leeward side of a mountainous area (away from the wind). The mountains block the passage of rain-producing weather systems and cast a "shadow" of dryness behind them. Wind and moist air is drawn by the prevailing winds towards the top of the mountains, where it condenses and precipitates before it crosses the top. The air, without much moisture left, advances behind the mountains creating a drier side called the "rain shadow".


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Q.7
The metabolic process which causes a reduction in gross primary production:
A. respiration
B. transportation
C. digestion
D. excretion
Answer : Option A
Explaination / Solution:

Respiration causes a reduction in gross primary productivity of an ecosystem. Gross primary productivity – Respiration = Net primary productivity.

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Q.8
Flow of energy in our ecosystem takes place
A. only in one direction
B. may occur in multiple directions
C. in three dimensions
D. possible in two directions
Answer : Option A
Explaination / Solution:

In ecosystem, flow of energy takes place in only one direction. The flow of energy takes place from producers to final consumers. Energy present in one trophic levels nevers return back to producer.

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Q.9
Which of the following is correct:
A. NPP – R = GPP
B. GPP + NPP = R
C. GPP – R = NPP
D. NPP – GPP = R
Answer : Option C
Explaination / Solution:

Net primary productivity (NPP) is equal to Gross primary productivity (GPP) minus Respiration loss (R). NPP is the available biomass for the consumption of heterotrophs in the ecosystem.

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Q.10
Producers in the aquatic ecosystem are :
A. Phytoplanktons
B. Shrubs
C. Herbacious plants
D. Zooplanktons
Answer : Option A
Explaination / Solution:

Phytoplanktons are small floating photosynthetic unicellular plant. In the aquatic ecosystem phytoplankton are producers that fix solar energy by the process of photosynthesis.

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