CSS :: Ecology and General Silviculture
141.
Hydrological cycle is under the control of:
A.
Grasslands
B.
Forests
C.
Planktons
D.
Epiphytes
Answer: Option B
Explanation:
142.
The maximum amount of CO2 fixed by green plants by way of photosynthesis in a year is:
A.
9 x 1013 kg
B.
8 x 1012 kg
C.
9 x 1011 kg
D.
8 x 1010 kg
Answer: Option A
Explanation:
143.
The sulphate rocks are formed in ocean by leaching of:
A.
FeS and Fe2S3
B.
Organic sulphates and -SH
C.
Soluble inorganic sulphates
D.
All of these
Answer: Option C
Explanation:
144.
Mark the incorrect statement with reference to carbon cycle:
A.
Lime rocks contribute to CO2 of water
B.
Atmospheric CO2 gets dissolved in water
C.
CO2 is returned by combustion of fuel
D.
75% of total carbon lies in geological component
Answer: Option D
Explanation:
145.
If we completely remove the decomposers from an ecosysters, its functioning will be adversely affected because:
A.
Herbivores will not receive solar energy
B.
Rate of decomposition of other component will be very high
C.
Mineral movement will be blocked
D.
Energy flow will be blocked
Answer: Option C
Explanation:
146.
Ecosystem receives nitrogen from outside through:
A.
Biological nitrogen fixation
B.
Electrification of nigrogen
C.
Industries
D.
All the above
Answer: Option D
Explanation:
147.
One of the major difficulties in the biological control of insect pests is that:
A.
The predator develops a preference to other diets and may itself become a pest
B.
They do not always survive when transferred to a new environment
C.
The method is less effective as compared to the use of insecticides
D.
The practical difficulty in introducing the predator to specific area
Answer: Option A
Explanation:
148.
Niche of a species in an ecosystem refers to its:
A.
Place of occurrence
B.
Competitive ability
C.
Centre of origin
D.
Function at its place of occurrence
Answer: Option D
Explanation:
149.
Energy transfer from one trophic level to other in a food chain is:
Answer: Option C
Explanation:
150.
The transfer of energy from one trophic level to another is governed by the 2nd law of thermodynamics. The average efficiency of energy transfer from nerbivores to carnivores is:
Answer: Option C
Explanation:
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