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Tuesday, August 27, 2019

Environment-ecology-Prelims booster quiz answer day-05

1.Biological Oxygen Demand (BOD) is a standard criterion for

(a) Measuring oxygen levels in blood
(b) Computing oxygen levels in forest ecosystems
(c) Pollution assay in aquatic ecosystems
(d) Assessing oxygen levels in high altitude regions
Answer-C
Biochemical Oxygen Demand (BOD, also called Biological Oxygen Demand) is the amount of dissolved oxygenneeded (i.e. demanded) by aerobic biological organisms to break down organic material present in a given water sample at certain temperature over a specific time period.

2.With reference to bio-toilets used by the Indian Railways, consider the following statements:
1. The decomposition of human waste in the bio-toilets in initiated by a fungal inoculum.
2.Ammonia and water vapour are the only end products in this decomposition which are released into the atmosphere.
Which of the statements given above is/are correct?
(a) 1 only
(b) 2 only
(c) Both 1 and 2
(d) Neither 1 nor 2
Answer-D
Bio-toilet is a decomposition mechanized toilet system which decomposes human excretory waste in the digester tank using specific high graded bacteria (aerobic or anaerobic) further converting it into methane gas, Carbon dioxide gas and water.

3.Which one of the following is the best description of the term 'ecosystem'?
(a) A community of organisms interacting with one another
(b) That part of the Earth which is inhabited by living organisms
(c) A community of organisms together with the environment in which they live
(d) The flora and fauna of a geographical area.
Answer-C
  • A community of organisms interacting with one another – no specific term.
  • That part of the Earth which is inhabited by living organisms ==> biosphere.
  • A community of organisms together with the environment in which they live ==> ecosystem.
  • The flora and fauna of a geographical area ==> biodiversity.

4.Lichens, which are capable of initiating ecolological succession even on a bare rock, are actually a symbiotic association of
(a) algae and bacteria
(b) algae and fungi
(c) bacteria and fungi
(d) fungi and mosses
Answer-B
In this association, the fungi (called mycobiont) facilitate water, minerals, vitamins, etc to the algae and algae (called phycobiont) prepare carbohydrate by the process of photosynthesis and supply the food to the fungi

5.With reference to Neem tree, consider the following statements :
1.Neem oil can be used as a pesticide to control the proliferation of some species of insects and mites.
2.Neem seeds are used in the manufacture of biofuels and hospital
3. Neem oil has applications in pharmaceutical industry.
Which of the statements given above is/are correct ?
(a) 1 and 2 only
(b) 3 only
(c) 1 and 3 only
(d) 1, 2 and 3
Answer-D



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